What will become of you when your master is gone? Will you be knocked down for a franc, when the family come to apportion my poor spoils? Will you be turned into a stand for the pitcher beside the kitchen sink? Will you be the plank on which the cabbages are shredded? Or will my children, on the contrary, agree and say:

'Let us preserve the relic. It was where he toiled so hard to teach himself and make himself capable of teaching others; it was where he so long consumed his strength to find food for us when we were little. Let us keep the sacred plank.'

I dare not believe in such a future for you. You will pass into strange hands, O my old friend; you will become a bedside table, laden with bowl after bowl of linseed tea, until, decrepit, rickety and broken down, you are chopped up to feed the flames for a brief moment under the simmering saucepan. You will vanish in smoke to join my labors in that other smoke, oblivion, the ultimate resting place of our vain agitations.

But let us return, little table, to our young days; those of your shining varnish and of my fond illusions. It is Sunday, the day of rest, that is to say, of continuous work, uninterrupted by my duties in the school. I greatly prefer Thursday, which is not a general holiday and more propitious to studious calm. Such as it is, for all its distractions, the Lord's day gives me a certain leisure. Let us make the most of it. There are fifty-two Sundays in the year, making a total that is almost equivalent to the long vacation.

It so happens that I have a glorious question to wrestle with today; that of Kepler's three laws, which, when explored by the calculus, are to show me the fundamental mechanism of the heavenly bodies. One of them says: 'The area swept out in a given time by the radius vector of the path of a planet is proportional to the time taken.'

From this I have to deduce that the force which confines the planet to its orbit is directed towards the sun. Gently entreated by the differential and integral calculus, already the formula is beginning to voice itself. My concentration redoubles, my mind is set upon seizing the radiant dawn of truth.

Suddenly, in the distance, br-r-r-rum! Br-r-r-rum! Br-r-r-rum! The noise comes nearer, grows louder. Woe upon me! And plague take the Pagoda!

Let me explain. I live in a suburb, at the beginning of the Pernes Road, far from the tumult of the town [of Carpentras where Fabre was a master at the college]. Twenty yards in front of my house, some pleasure gardens have been opened, bearing a signboard inscribed, 'The Pagoda.' Here, on Sunday afternoons, the lads and lasses from the neighboring farms come to disport themselves in country dances. To attract custom and push the sale of refreshments, the proprietor of the ball ends the Sunday hop with a tombola. Two hours beforehand, he has the prizes carried along the public roads, preceded by fifes and drums. From a beribboned pole, borne by a stalwart fellow in a red sash, dangle a plated goblet, a handkerchief of Lyons silk, a pair of candlesticks and some packets of cigars. Who would not enter the pleasure gardens, with such a bait?

'Br-r-r-rum! Br-r-r-rum! Br-r-r-rum!' goes the procession.

It comes just under my window, wheels to the right and marches into the establishment, a huge wooden booth, hung with evergreens. And now, if you dislike noise, flee, flee as far as you can. Until nightfall, the ophicleides will bellow, the fifes tootle and the cornets bray. How would you deduce the steps of Kepler's laws to the accompaniment of that noisy orchestra! It is enough to drive one mad. Let us be off with all speed.

A mile away, I know a flinty waste beloved of the wheatear and the locust. Here reigns perfect calm; moreover, there are some clumps of evergreen oak which will lend me their scanty shade. I take my book, a few sheets of paper and a pencil and fly to this solitude. What beauteous silence, what exquisite quiet! But the sun is overwhelming, under the meager cover of the bushes. Cheerily, my lad! Have at your Kepler's laws in the company of the blue-winged locusts. You will return home with your problems solved, but with a blistered skin. An overdose of sun in the neck shall be the outcome of grasping the law of the areas. One thing makes up for another.

During the rest of the week, I have my Thursdays and the evenings, which I employ in study until I drop with sleep. All told I have no lack of time, despite the drudgery of my college ties. The great thing is not to be discouraged by the unavoidable difficulties encountered at the outset. I lose my way easily in that dense forest overgrown with creepers that have to be cut away with the axe to obtain a clearing. A fortunate turn or two; and I once more know where I am. I lose my way again. The stubborn axe makes its opening without always letting in sufficient light.

The book is just a book, that is to say, a set text, saying not a word more than it is obliged to, exceedingly learned, I admit, but, alas, often obscure! The author, it seems, wrote it for himself. He understood; therefore others must. Poor beginners, left to yourselves, you manage as best you can! For you, there shall be no retracing of steps in order to tackle the difficulty in another way; no circuit easing the arduous road and preparing the passage; no supplementary aperture to admit a glimmer of daylight. Incomparably inferior to the spoken word, which begins again with fresh methods of attack and is ready to vary the paths that lead to the open, the book says what it says and nothing more. Having finished its demonstration, whether you understand or no, the oracle is inexorably dumb. You reread the text and ponder it obstinately; you pass and repass your shuttle through the woof of figures. Useless efforts all: the darkness continues. What would be needed to supply the illuminating ray? Often enough, a trifle, a mere word; and that word the book will not speak.

Happy is he who is guided by a master's teaching! His progress does not know the misery of those wearisome breakdowns. What was I to do before the disheartening wall that every now and then rose up and barred my road? I followed d'Alembert's precept in his advice to young mathematical students: 'Have faith and go ahead,' said the great geometrician.

Faith I had; and I went on pluckily. And it was well for me that I did, for I often found behind the wall the enlightenment which I was seeking in front of it. Giving up the bad patch as hopeless, I would go on and, after I had left it behind, discover the dynamite capable of blasting it. 'Twas a tiny grain at first, an insignificant ball rolling and increasing as it went. From one slope to the other of the theorems, it grew to a heavy mass; and the mass became a mighty projectile which, flung backwards and retracing its course, split the darkness and spread it into one vast sheet of light.

D'Alembert's precept is good and very good, provided you do not abuse it. Too much precipitation in turning over the intractable page might expose you to many a disappointment. You must have fought the difficulty tooth and nail before abandoning it. This rough skirmishing leads to intellectual vigor.

Twelve months of meditation in the company of my little table at last won me my degree as a licentiate of mathematical science; and I was now qualified to perform, half a century later, the eminently lucrative functions of an inspector of Spiders' webs!



CHAPTER XIV. THE BLUEBOTTLE: THE LAYING

To purge the earth of death's impurities and cause deceased animal matter to be once more numbered among the treasures of life there are hosts of sausage queens, including, in our part of the world, the bluebottle (Calliphora vomitaria, LIN.) and the checkered flesh fly (Sarcophaga carnaria, LIN.). Every one knows the first, the big, dark-blue fly who, after effecting her designs in the ill-watched meat safe, settles on our window panes and keeps up a solemn buzzing, anxious to be off in the sun and ripen a fresh emission of germs. How does she lay her eggs, the origin of the loathsome maggot that battens poisonously on our provisions, whether of game or butcher's meat? What are her stratagems and how can we foil them? This is what I propose to investigate.

The bluebottle frequents our homes during autumn and a part of winter, until the cold becomes severe; but her appearance in the fields dates back much earlier. On the first fine day in February, we shall see her warming herself, chillily, against the sunny walls. In April, I notice her in considerable numbers on the laurestinus. It is here that she seems to pair, while sipping the sugary exudations of the small white flowers. The whole of the summer season is spent out of doors, in brief flights from one refreshment bar to the next. When autumn comes, with its game, she makes her way into our houses and remains until the hard frosts.

This suits my stay-at-home habits and especially my legs, which are bending under the weight of years. I need not run after the subjects of my present study; they call on me. Besides, I have vigilant assistants. The household knows of my plans. Every one brings me, in a little screw of paper, the noisy visitor just captured against the panes.

Thus do I fill my vivarium, which consists of a large, bell-shaped cage of wire gauze, standing in an earthenware pan full of sand. A mug containing honey is the dining room of the establishment. Here the captives come to recruit themselves in their hours of leisure. To occupy their maternal cares, I employ small birds—chaffinches, linnets, sparrows—brought down, in the enclosure, by my son's gun.

I have just served up a Linnet shot two days ago. I next place in the cage a bluebottle, one only, to avoid confusion. Her fat belly proclaims the advent of a laying time. An hour later, when the excitement of being put in prison is allayed, my captive is in labor. With eager, jerky steps, she explores the morsel of game, goes from the head to the tail, returns from the tail to the head, repeats the action several times and at last settles near an eye, a dimmed eye sunk into its socket.

The ovipositor bends at a right angle and dives into the junction of the beak, straight down to the root. Then the eggs are emitted for nearly half an hour. The layer, utterly absorbed in her serious business, remains stationary and impassive and is easily observed through my lens. A movement on my part would doubtless scare her; but my restful presence gives her no anxiety. I am nothing to her.

The discharge does not go on continuously until the ovaries are exhausted; it is intermittent and performed in so many packets. Several times over, the fly leaves the bird's beak and comes to take a rest upon the wire gauze, where she brushes her hind legs one against the other. In particular, before using it again, she cleans, smoothes and polishes her laying tool, the probe that places the eggs. Then, feeling her womb still teeming, she returns to the same spot at the joint of the beak. The delivery is resumed, to cease presently and then begin anew. A couple of hours are thus spent in alternate standing near the eye and resting on the wire gauze.

At last, it is over. The fly does not go back to the bird, a proof that her ovaries are exhausted. The next day, she is dead. The eggs are dabbed in a continuous layer, at the entrance to the throat, at the root of the tongue, on the membrane of the palate. Their number appears considerable; the whole inside of the gullet is white with them. I fix a little wooden prop between the two mandibles of the beak, to keep them open and enable me to see what happens.

I learn in this way that the hatching takes place in a couple of days. As soon as they are born, the young vermin, a swarming mass, leave the place where they are and disappear down the throat. To inquire further into the work is useless for the moment. We shall learn more about it later, under conditions that make examination easier.

The beak of the bird invaded was closed at the start, as far as the natural contact of the mandibles allowed. There remained a narrow slit at the base, sufficient at most to admit the passage of a horsehair. It was through this that the laying was performed. Lengthening her ovipositor like a telescope, the mother inserted the point of her implement, a point slightly hardened with a horny armor. The fineness of the probe equals the fineness of the aperture. But, if the beak were entirely closed, where would the eggs be laid then?

With a tied thread, I keep the two mandibles in absolute contact; and I place a second bluebottle in the presence of the linnet, which the colonists have already entered by the beak. This time, the laying takes place on one of the eyes, between the lid and the eyeball. At the hatching, which again occurs a couple of days later, the grubs make their way into the fleshy depths of the socket. The eyes and the beak, therefore, form the two chief entrances into feathered game.

There are others; and these are the wounds. I cover the linnet's head with a paper hood which will prevent invasion through the beak and eyes. I serve it, under the wire gauze bell, to a third egg layer. The bird has been struck by a shot in the breast, but the sore is not bleeding: no outer stain marks the injured spot. Moreover, I am careful to arrange the feathers, to smooth them with a hair pencil, so that the bird looks quite smart and has every appearance of being untouched.

The fly is soon there. She inspects the linnet from end to end; with her front tarsi she fumbles at the breast and belly. It is a sort of auscultation by sense of touch. The insect becomes aware of what is under the feathers by the manner in which these react. If scent comes to her assistance, it can only be very slightly, for the game is not yet high. The wound is soon found. No drop of blood is near it, for it is closed by a plug of down rammed into it by the shot. The fly takes up her position without separating the feathers or uncovering the wound. She remains here for two hours without stirring, motionless, with her abdomen concealed beneath the plumage. My eager curiosity does not distract her from her business for a moment.

When she has finished, I take her place. There is nothing either on the skin or at the mouth of the wound. I have to withdraw the downy plug and dig to some depth before discovering the eggs. The ovipositor has therefore lengthened its extensible tube and pushed beyond the feather stopper driven in by the lead. The eggs are in one packet; they number about three hundred.

When the beak and eyes are rendered inaccessible, when the body, moreover, has no wounds, the laying still takes place, but, this time, in a hesitating and niggardly fashion. I pluck the bird completely, the better to watch what happens; also, I cover the head with a paper hood to close the usual means of access. For a long time, with jerky steps, the mother explores the body in every direction; she takes her stand by preference on the head, which she sounds by tapping on it with her front tarsi. She knows that the openings which she needs are there, under the paper; but she also knows how frail are her grubs, how powerless to pierce their way through the strange obstacle which stops her as well and interferes with the work of her ovipositor. The cowl inspires her with profound distrust. Despite the tempting bait of the veiled head, not an egg is laid on the wrapper, slight though it may be.

Weary of vain attempts to compass this obstacle, the Fly at last decides in favor of other points, but not on the breast, belly or back, where the hide would seem too tough and the light too intrusive. She needs dark hiding places, corners where the skin is very delicate. The spots chosen are the cavity of the axilla, corresponding with our armpit, and the crease where the thigh joins the belly. Eggs are laid in both places, but not many, showing that the groin and the axilla are adopted only reluctantly and for lack of a better spot.

With an unplucked bird, also hooded, the same experiment failed: the feathers prevent the fly from slipping into those deep places. Let us add, in conclusion, that, on a skinned bird, or simply on a piece of butcher's meat, the laying is effected on any part whatever, provided that it be dark. The gloomiest corners are the favorite ones.

It follows from all this that, to lay the eggs, the Bluebottle picks out either naked wounds or else the mucous membranes of the mouth or eyes, which are not protected by a skin of any thickness. She also needs darkness. We shall see the reasons for her preference later on.

The perfect efficiency of the paper bag, which prevents the inroads of the worms through the eye sockets or the beak, suggests a similar experiment with the whole bird. It is a matter of wrapping the body in a sort of artificial skin which will be as discouraging to the fly as the natural skin. Linnets, some with deep wounds, others almost intact, are placed one by one in paper envelopes similar to those in which the nursery gardener keeps his seeds, envelopes just folded, without being stuck. The paper is quite ordinary and of average thickness. Torn pieces of newspaper serve the purpose.

These sheaths with the corpses inside them are freely exposed to the air, on the table in my study, where they are visited, according to the time of day, in dense shade and in bright sunlight. Attracted by the effluvia from the dead meat, the bluebottles haunt my laboratory, the windows of which are always open. I see them daily alighting on the envelopes and very busily exploring them, apprised of the contents by the gamy smell. Their incessant coming and going is a sign of intense cupidity; and yet none of them decides to lay on the bags. They do not even attempt to slide their ovipositor through the slits of the folds. The favorable season passes and not an egg is laid on the tempting wrappers. All the mothers abstain, judging the slender obstacle of the paper to be more than the vermin will be able to overcome.

This caution on the fly's part does not at all surprise me: motherhood everywhere has gleams of great perspicacity. What does astonish me is the following result. The parcels containing the linnets are left for a whole year uncovered on the table; they remain there for a second year and a third. I inspect the contents from time to time. The little birds are intact, with unrumpled feathers, free from smell, dry and light, like mummies. They have become not decomposed, but mummified.

I expected to see them putrefying, running into sanies, like corpses left to rot in the open air. On the contrary, the birds have dried and hardened, without undergoing any change. What did they want for their putrefaction? Simply the intervention of the fly. The maggot, therefore, is the primary cause of dissolution after death; it is, above all, the putrefactive chemist.

A conclusion not devoid of value may be drawn from my paper game bags. In our markets, especially in those of the South, the game is hung unprotected from the hooks on the stalls. Larks strung up by the dozen with a wire through their nostrils, thrushes, plovers, teal, partridges, snipe, in short, all the glories of the spit which the autumn migration brings us, remain for days and weeks at the mercy of the flies. The buyer allows himself to be tempted by a goodly exterior; he makes his purchase and, back at home, just when the bird is being prepared for roasting, he discovers that the promised dainty is alive with worms. O horror! There is nothing for it but to throw the loathsome, verminous thing away.

The bluebottle is the culprit here. Everybody knows it; and nobody thinks of seriously shaking off her tyranny: not the retailer, nor the wholesale dealer, nor the killer of the game. What is wanted to keep the maggots out? Hardly anything: to slip each bird into a paper sheath. If this precaution were taken at the start, before the flies arrive, any game would be safe and could be left indefinitely to attain the degree of ripeness required by the epicure's palate.

Stuffed with olives and myrtle berries, the Corsican blackbirds are exquisite eating. We sometimes receive them at Orange, layers of them, packed in baskets through which the air circulates freely and each contained in a paper wrapper. They are in a state of perfect preservation, complying with the most exacting demands of the kitchen. I congratulate the nameless shipper who conceived the bright idea of clothing his blackbirds in paper. Will his example find imitators? I doubt it.

There is, of course, a serious objection to this method of preservation. In its paper shroud, the article is invisible; it is not enticing; it does not inform the passer by of its nature and qualities. There is one resource left which would leave the bird uncovered: simply to case the head in a paper cap. The head being the part most threatened, because of the mucus membrane of the throat and eyes, it would be sufficient, as a rule, to protect the head, in order to keep off the Flies and to thwart their attempts.

Let us continue to study the bluebottle, while varying our means of information. A tin, about four inches deep, contains a piece of butcher's meat. The lid is not put in quite straight and leaves a narrow slit at one point of its circumference, allowing, at most, of the passage of a fine needle. When the bait begins to give off a gamy scent, the mothers come. Singly or in numbers. They are attracted by the odor which, transmitted through a thin crevice, hardly reaches my nostrils.

They explore the metal receptacle for some time, seeking an entrance. Finding naught that enables them to reach the coveted morsel, they decide to lay their eggs on the tin, just beside the aperture. Sometimes, when the width of the passage allows of it, they insert the ovipositor into the tin and lay the eggs inside, on the very edges of the slit. Whether outside or in, the eggs are dabbed down in a fairly regular and absolutely white layer. I as it were shovel them up with a little paper scoop. I thus obtain all the germs that I require for my experiments, eggs bearing no trace of the stains which would be inevitable if I had to collect them on tainted meat.

We have seen the bluebottle refusing to lay her eggs on the paper bag, notwithstanding the carrion fumes of the Linnet enclosed; yet now, without hesitation, she lays them on a sheet of metal. Can the nature of the floor make any difference to her? I replace the tin lid by a paper cover stretched and pasted over the orifice. With the point of my knife, I make a narrow slit in this new lid. That is quite enough: the parent accepts the paper.

What determined her, therefore, is not simply the smell, which can easily be perceived even through the uncut paper, but, above all, the crevice, which will provide an entrance for the vermin, hatched outside, near the narrow passage. The maggots' mother has her own logic, her prudent foresight. She knows how feeble her wee grubs will be, how powerless to cut their way through an obstacle of any resistance; and so, despite the temptation of the smell, she refrains from laying so long as she finds no entrance through which the newborn worms can slip unaided.

I wanted to know whether the color, the shininess, the degree of hardness and other qualities of the obstacle would influence the decision of a mother obliged to lay her eggs under exceptional conditions. With this object in view, I employed small jars, each baited with a bit of butcher's meat. The respective lids were made of different colored paper, of oilskin, or of some of that tinfoil, with its gold or coppery sheen, which is used for sealing liqueur bottles. On not one of these covers did the mothers stop, with any desire to deposit their eggs; but, from the moment that the knife had made the narrow slit, all the lids were, sooner or later, visited and all of them, sooner or later, received the white shower somewhere near the gash. The look of the obstacle, therefore, does not count; dull or brilliant, drab or colored: these are details of no importance; the thing that matters is that there should be a passage to allow the grubs to enter.

Though hatched outside, at a distance from the coveted morsel, the newborn worms are well able to find their refectory. As they release themselves from the egg, without hesitation, so accurate is their scent, they slip beneath the edge of the ill-joined lid, or through the passage cut by the knife. Behold them entering upon their promised land, their reeking paradise.

Eager to arrive, do they drop from the top of the wall? Not they! Slowly creeping, they make their way down the side of the jar; they use their fore part, ever in quest of information, as a crutch and grapnel in one. They reach the meat and at once install themselves upon it.

Let us continue our investigation, varying the conditions. A large test-tube, measuring nine inches high, is baited at the bottom with a lump of butcher's meat. It is closed with wire gauze, whose meshes, two millimeters wide, do not permit of the fly's passage. The bluebottle comes to my apparatus, guided by scent rather than sight. She hastens to the test tube whose contents are veiled under an opaque cover with the same alacrity as to the open tube. The invisible attracts her quite as much as the visible.

She stays a while on the lattice of the mouth, inspects it attentively; but, whether because circumstances have failed to serve me, or because the wire network inspires her with distrust, I never saw her dab her eggs upon it for certain. As her evidence was doubtful, I had recourse to the flesh fly (Sarcophaga carnaria).

This fly is less finicky in her preparations, she has more faith in the strength of her worms, which are born ready-formed and vigorous, and easily shows me what I wish to see. She explores the trellis-work, chooses a mesh through which she inserts the tip of her abdomen and, undisturbed by my presence, emits, one after the other, a certain number of grubs, about ten or so. True, her visits will be repeated, increasing the family at a rate of which I am ignorant.

The newborn worms, thanks to a slight viscidity, cling for a moment to the wire gauze; they swarm, wriggle, release themselves and leap into the chasm. It is a nine inch drop at least. When this is done, the mother makes off, knowing for a certainty that her offspring will shift for themselves. If they fall on the meat, well and good; if they fall elsewhere, they can reach the morsel by crawling.

This confidence in the unknown factor of the precipice, with no indication but that of smell, deserves fuller, investigation. From what height will the flesh fly dare to let her children drop? I top the test-tube with another tube, the width of the neck of a claret bottle. The mouth is closed either with wire gauze, or with a paper cover with a slight cut in it. Altogether, the apparatus measures twenty-five inches in height. No matter: the fall is not serious for the lithe backs of the young grubs; and, in a few days, the test-tube is filled with larvae, in which it is easy to recognize the flesh fly's family by the fringed coronet that opens and shuts at the maggot's stern like the petals of a little flower. I did not see the mother operating: I was not there at the time; but there is no doubt possible of her coming nor of the great dive taken by the family: the contents of the test-tube furnish me with a duly authenticated certificate.

I admire the leap and, to obtain one better still, I replace the tube by another, so that the apparatus now stands forty-six inches high. The column is erected at a spot frequented by flies, in a dim light. Its mouth, closed with a wire gauze cover, reaches the level of various other appliances, test-tubes and jars, which are already stocked or awaiting their colony of vermin. When the position is well known to the flies, I remove the other tubes and leave the column, lest the visitors should turn aside to easier ground.

From time to time, the bluebottle and the flesh fly perch on the trellis-work, make a short investigation and then decamp. Throughout the summer season, for three whole months, the apparatus remains where it is, without the least result: never a worm. What is the reason? Does the stench of the meat not spread, coming from that depth? Certainly it spreads: it is unmistakable to my dulled nostrils and still more so to the nostrils of my children, whom I call to bear witness. Then why does the flesh fly, who but now was dropping her grubs from a goodly height, refuse to let them fall from the top of a column twice as high? Does she fear lest her worms should be bruised by an excessive drop? There is nothing about her to point to anxiety aroused by the length of the shaft. I never see her explore the tube or take its size. She stands on the trellised orifice; and there the matter ends. Can she be apprised of the depth of the chasm by the comparative faintness of the offensive odors that arise from it? Can the sense of smell measure the distance and judge whether it be acceptable or not? Perhaps.

The fact remains that, despite the attraction of the scent, the flesh fly does not expose her worms to disproportionate falls. Can she know beforehand that, when the chrysalides break, her winged family, knocking with a sudden flight against the sides of a tall chimney, will be unable to get out? This foresight would be in agreement with the rules which order maternal instinct according to future needs.

But when the fall does not exceed a certain depth, the budding worms of the flesh fly are dropped without a qualm, as all our experiments show. This principle has a practical application which is not without its value in matters of domestic economy. It is as well that the wonders of entomology should sometimes give us a hint of commonplace utility.

The usual meat safe is a sort of large cage with a top and bottom of wood and four wire gauze sides. Hooks fixed into the top are used whereby to hang pieces which we wish to protect from the flies. Often, so as to employ the space to the best advantage, these pieces are simply laid on the floor on the cage. With these arrangements, are we sure of warding off the fly and her vermin?

Not at all. We may protect ourselves against the Bluebottle, who is not much inclined to lay her eggs at a distance from the meat; but there is still the flesh fly, who is more venturesome and goes more briskly to work and who will slip the grubs through a hole in the meshes and drop them inside the safe. Agile as they are and well able to crawl, the worms will easily reach anything on the floor; the only things secure from their attacks will be the pieces hanging from the ceiling. It is not in the nature of maggots to explore the heights, especially if this implies climbing down a string in addition.

People also use wire gauze dish covers. The trellised dome protects the contents even less than does the meat safe. The flesh fly takes no heed of it. She can drop her worms through the meshes on the covered joint.

Then what are we to do? Nothing could be simpler. We need only wrap the birds which we wish to preserve—thrushes, partridges, snipe and so on—in separate paper envelopes; and the same with our beef and mutton. This defensive armor alone, while leaving ample room for the air to circulate, makes any invasion by the worms impossible, even without a cover or a meat safe: not that paper possesses any special preservative virtues, but solely because it forms an impenetrable barrier. The Bluebottle carefully refrains from laying her eggs upon it and the flesh fly from bringing forth her offspring, both of them knowing that their newborn young are incapable of piercing the obstacle.

Paper is equally successful in our strife against the Moths, those plagues of our furs and clothes. To keep away these wholesale ravages, people generally use camphor, naphthalene, tobacco, bunches of lavender and other strong-scented remedies. Without wishing to malign those preservatives, we are bound to admit that the means employed are none too effective. The smell does very little to prevent the havoc of the moths.

I would therefore counsel our housewives, instead of all this chemist's stuff, to use newspapers of a suitable shape and size. Take whatever you wish to protect—your furs, your flannel or your clothes—and pack each article carefully in a newspaper, joining the edges with a double fold, well pinned. If this joining is properly done, the Moth will never get inside. Since my advice has been taken and this method employed in my household, the old damage has never been repeated.

To return to the fly. A piece of meat is hidden in a jar under a layer of fine, dry sand, a finger's-breadth thick. The jar has a wide mouth and is left quite open. Let whoever come that will, attracted by the smell. The Bluebottles are not long in inspecting what I have prepared for them: they enter the jar, go out and come back again, inquiring into the invisible thing revealed by its fragrance. A diligent watch enables me to see them fussing about, exploring the sandy expanse, tapping it with their feet, sounding it with their proboscis. I leave the visitors undisturbed for a fortnight or three weeks. None of them lays any eggs.

This is a repetition of what the paper bag, with its dead bird, showed me. The flies refuse to lay on the sand, apparently for the same reasons. The paper was considered an obstacle which the frail vermin would not be able to overcome. With sand, the case is worse. Its grittiness would hurt the newborn weaklings, its dryness would absorb the moisture indispensable to their movements. Later, when preparing for the metamorphosis, when their strength has come to them, the grubs will dig the earth quite well and be able to descend; but, at the start, that would be very dangerous for them. Knowing these difficulties, the mothers, however greatly tempted by the smell, abstain from breeding. As a matter of fact, after long waiting, fearing lest some packets of eggs may have escaped my attention, I inspect the contents of the jar from top to bottom. Meat and sand contain neither larvae nor pupae: the whole is absolutely deserted.

The layer of sand being only a finger's-breadth thick, this experiment requires certain precautions. The meat may expand a little, in going bad, and protrude in one or two places. However small the fleshy eyots that show above the surface, the flies come to them and breed. Sometimes also the juices oozing from the putrid meat soak a small extent of the sandy floor. That is enough for the maggot's first establishment. These causes of failure are avoided with a layer of sand about an inch thick. Then the bluebottle, the flesh fly and other flies whose grubs batten on dead bodies are kept at a proper distance.

In the hope of awakening us to a proper sense of our insignificance, pulpit orators sometimes make an unfair use of the grave and its worms. Let us put no faith in their doleful rhetoric. The chemistry of man's final dissolution is eloquent enough of our emptiness: there is no need to add imaginary horrors. The worm of the sepulchre is an invention of cantankerous minds, incapable of seeing things as they are. Covered by but a few inches of earth, the dead can sleep their quiet sleep: no fly will ever come to take advantage of them.

At the surface of the soil, exposed to the air, the hideous invasion is possible; ay, it is the invariable rule. For the melting down and remolding of matter, man is no better, corpse for corpse, than the lowest of the brutes. Then the fly exercises her rights and deals with us as she does with any ordinary animal refuse. Nature treats us with magnificent indifference in her great regenerating factory: placed in her crucibles, animals and men, beggars and kings are one and all alike. There you have true equality, the only equality in this world of ours: equality in the presence of the maggot.



CHAPTER XV. THE BLUEBOTTLE: THE GRUB

The larvae of the bluebottle hatch within two days in the warm weather. Whether inside my apparatus, in direct contact with the piece of meat, or outside, on the edge of a slit that enables them to enter, they set to work at once. They do not eat, in the strict sense of the word, that is to say, they do not tear their food, do not chew it by means of implements of mastication. Their mouth parts do not lend themselves to this sort of work. These mouth parts are two horny spikes, sliding one upon the other, with curved ends that do not face, thus excluding the possibility of any function such as seizing and grinding.

The two guttural grapnels serve for walking much rather than for feeding. The worm plants them alternately in the road traversed and, by contracting its crupper, advances just that distance. It carries in its tubular throat the equivalent of our iron tipped sticks which give support and assist progress.

Thanks to this machinery of the mouth, the maggot not only moves over the surface, but also easily penetrates the meat: I see it disappear as though it were dipping into butter. It cuts its way, levying, as it goes, a preliminary toll, but only of liquid mouthfuls. Not the smallest solid particle is detached and swallowed. That is not the maggot's diet. It wants a broth, a soup, a sort of fluid extract of beef which it prepares itself. As digestion, after all, merely means liquefaction, we may say, without being guilty of paradox, that the grub of the bluebottle digests its food before swallowing it.

With the object of relieving gastric troubles, our manufacturing chemists scrape the stomachs of the pig and sheep and thus obtain pepsin, a digestive agent which possesses the property of liquefying albuminous matters and lean meat in particular. Why cannot they rasp the stomach of the maggot! They would obtain a product of the highest quality, for the carnivorous worm also owns its pepsin, pepsin of a singularly active kind, as the following experiments will show us.

I divide the white of a hard-boiled egg into tiny cubes and place them in a little test-tube. On the top of the contents, I sprinkle the eggs of the bluebottle, eggs free from the least stain, taken from those laid on the outside of tins baited with meat and not absolutely shut. A similar test-tube is filled with white of egg, but receives no germs. Both are closed with a plug of cotton-wool and left in a dark corner.

In a few days, the tube swarming with newborn vermin contains a liquid as fluid and transparent as water. Not a drop would remain in the tube if I turned it upside down. All the white of egg has disappeared, liquefied. As for the worms, which are already a fair size, they seem very ill at ease. Deprived of a support whence to attain the outer air, most of them dive into the broth of their own making, where they perish by drowning. Others, endowed with greater vigor, crawl up the glass to the plug and manage to make their way through the wadding. Their pointed front, armed with grappling irons, is the nail that penetrates the fibrous mass.

In the other test-tube, standing beside the first and subjected to the same atmospheric influences, nothing striking has occurred. The hard-boiled white of egg has retained its dead white color and its firmness. I find it as I left it. The utmost that I observe is a few traces of must. The result of this first experiment is patent: the Bluebottle's grub is the medium that converts coagulated albumen into a liquid.

The value of chemist's pepsin is estimated by the quantity of hard-boiled white of egg which a gram of that agent can liquefy. The mixture has to be exposed in an oven to a temperature of 1400 F. and also to be frequently shaken. My preparation, in which the bluebottle's eggs are hatched, is neither shaken nor subjected to the heat of an oven; everything happens in quietness and under the thermometric conditions of the surrounding air; nevertheless, in a few days, the coagulated albumen, treated by the vermin, runs like water.

The reagent that causes this liquefaction escapes my endeavors to detect it. The worms must disgorge it in infinitesimal doses, while the spikes in their throats, which are in continual movement, emerge a little way from the mouth, reenter and reappear. Those piston thrusts, those quasi-kisses, are accompanied by the emission of the solvent: at least, that is how I picture it. The maggot spits on its food, places on it the wherewithal to make it into broth. To appraise the quantity of the matter expectorated is beyond my powers: I observe the result, but do not perceive the leavening agent.

Well, this result is really astounding, when we consider the scantiness of the means. No pig's or sheep's pepsin can rival that of the worm. I have a bottle of pepsin that comes from the School of Chemistry at Montpellier. I lavishly powder some pieces of hard-boiled white of egg with the potent drug, just as I did with the eggs of the Bluebottle. The oven is not brought into play, neither is distilled water added, nor hydrochloric acid: two auxiliaries which are recommended. The experiment is conducted in exactly the same way as that of the tubes with the vermin. The result is entirely different from what I expected. The white of egg does not liquefy. It simply becomes moist on the surface; and even this moisture may come from the pepsin, which is highly absorbent. Yes, I was right: if the thing were feasible, it would be an advantage for the chemists to collect their digestive drug from the stomach of the maggot. The worm, in this case, beats the pig and the sheep.

The same method is followed for the remaining experiments. I put the bluebottle's eggs to hatch on a piece of meat and leave the worms to do their work as they please. The lean tissues, whether of mutton, beef or pork, no matter which, are not turned into liquid; they become a pea soup of a clarety brown. The liver, the lung, the spleen are attacked to better purpose, without, however, getting beyond the state of a semi-fluid jam, which easily mixes with water and even appears to dissolve in it. The brains do not liquefy either: they simply melt into a thin gruel.

On the other hand, fatty substances, such as beef suet, lard and butter, do not undergo any appreciable change. Moreover, the worms soon dwindle away, incapable of growing. This sort of food does not suit them. Why? Apparently because it cannot be liquefied by the reagent disgorged by the worms. In the same way, ordinary pepsin does not attack fatty substances; it takes pancreatin to reduce them to an emulsion. This curious analogy of properties, positive for albuminous, negative for fatty matter, proclaims the similarity and perhaps the identity of the dissolvent discharged by the grubs and the pepsin of the higher animals.

Here is another proof: the usual pepsin does not dissolve the epidermis, which is a material of a horny nature. That of the maggots does not dissolve it either. I can easily rear bluebottle grubs on dead crickets whose bellies I have first opened; but I do not succeed if the morsel be left intact: the worms are unable to perforate the succulent paunch; they are stopped by the cuticle, on which their reagent refuses to act. Or else I give them frogs' hind legs, stripped of their skin. The flesh turns to broth and disappears to the bone. If I do not peel the legs, they remain intact in the midst of the vermin. Their thin skin is sufficient to protect them.

This failure to act upon the epidermis explains why the bluebottle at work on the animal declines to lay her eggs on the first part that comes handy. She needs the delicate membrane of the nostrils, eyes or throat, or else some wound in which the flesh is laid bare. No other place suits her, however excellent for flavor and darkness. At most, finding nothing better when my stratagems interfere, she persuades herself to dab a few eggs under the axilla of a plucked bird or in the groin, two points at which the skin is thinner than elsewhere.

With her maternal foresight, the bluebottle knows to perfection the choice surfaces, the only ones liable to soften and run under the influence of the reagent dribbled by the newborn grubs. The chemistry of the future is familiar to her, though she does not use it for her own feeding; motherhood, that great inspirer of instinct, teaches her all about it.

Scrupulous though she be in choosing exactly where to lay her eggs, the bluebottle does not trouble about the quality of the provisions intended for her family's consumption. Any dead body suits her purpose. Redi, the Italian scientist who first exploded the old, foolish notion of worms begotten of corruption, fed the vermin in his laboratory with meat of very different kinds. In order to make his tests the more conclusive, he exaggerated the largess of the dining hall. The diet was varied with tiger and lion flesh, bear and leopard, fox and wolf, mutton and beef, horseflesh, donkey flesh and many others, supplied by the rich menagerie of Florence. This wastefulness was unnecessary: wolf and mutton are all the same to an unprejudiced stomach.

A distant disciple of the maggot's biographer, I look at the problem in a light which Redi never dreamt of. Any flesh of one of the higher animals suits the fly's family. Will it be the same if the food supplied be of a lower organism and consist of fish, for instance, of frog, mollusk, insect, centipede? Will the worms accept these viands and, above all, can they manage to liquefy them, which is the first and foremost condition?

I serve a piece of raw whiting. The flesh is white, delicate, partly translucent, easy for our stomachs to digest and no less suited to the grub's dissolvent. It turns into an opalescent fluid, which runs like water. In fact, it liquefies in much the same way as hard-boiled white of egg. The worms at first wax fat, as long as the conditions allow of some solid eyots remaining; then, when foothold fails, threatened with drowning in the too fluid broth, they creep up the side of the glass, anxious and restless to be off. They climb to the cotton-wool stopper of the test-tube and try to bolt through the wadding. Endowed with stubborn perseverance, nearly all of them decamp in spite of the obstacle. The test-tube with the white of egg showed me a similar exodus. Although the fare suits them, as their growth witnesses, the worms cease feeding and make a point of escaping when death by drowning is imminent.

With other fish, such as skate and sardines, with the flesh of frogs and tree frogs, the meat simply dissolves into a porridge. Hashes of slug, Scolopendra or praying mantis furnish the same result.

In all these preparations, the dissolving agent of the worms is as much in evidence as when butcher's meat is employed. Moreover, the grubs seem satisfied with the queer dish which my curiosity prescribes for them; they thrive amidst the victuals and undergo their transformation into pupae.

The conclusion, therefore, is much more general than Redi imagined. Any meat, no matter whether of a higher or lower order, suits the bluebottle for the settlement of her family. The carcasses of furred and feathered animals are the favorite victuals, probably because of their richness, which allows of plentiful layings; but, should the occasion demand it, the others are also accepted, without inconvenience. Any carrion that has lived the life of an animal comes within the domain of these scavengers.

What is their number to one mother? I have already spoken of a deposit of three hundred, counted egg by egg. A quite fortuitous circumstance enabled me to go much farther. In the first week of January 1905, we experienced a sudden short cold snap of a severity very exceptional in my part of the country. The thermometer fell to twelve degrees below zero. While a fierce north wind was raging and beginning to redden the leaves of the olive trees, came one and brought me a barn or screech owl, which he had found on the ground, exposed to the air, not far from my house. My reputation as a lover of animals made the donor believe that I should be pleased with his gift.

I was, as a matter of fact, but for reasons whereof the finder certainly never dreamt. The owl was untouched, with trim feathers and not the least wound that showed. Perhaps he had died of cold. What made me gratefully accept the present was exactly that which would have inclined anyone but myself to refuse it. The owl's eyes, glazed in death, were hidden under a thick mass of eggs, which I recognized as a bluebottle's. Similar masses occupied the vicinity of the nostrils. If I wanted maggots, here, of a certainty, was a richer crop than I had ever beheld.

I place the corpse on the sand of a pan, with a wire gauze cover, and leave events to take their course. The laboratory in which I install my bird is none other than my study. It is as cold in there, or nearly, as outside, so much so that the water in the aquarium in which I used to rear caddis worms has frozen into a solid block of ice. Under these conditions of temperature, the owl's eyes keep their white veil of germs unchanged. Nothing stirs, nothing swarms. Weary of waiting, I pay no more attention to the carcass; I leave the future to decide whether the cold has exterminated the fly's family or not.

Before the end of March, the packets of eggs have disappeared, I know not how long. The bird, for that matter, seems to be intact. On the ventral surface, which is turned to the air, the feathers keep their smooth arrangement and their fresh coloring. I lift the thing. It is light, very dry and gives a hard sound, like an old shoe tanned by the summer sun in the fields. There is no smell. The dryness has vanquished the stench, which, in any case, was never offensive during that time of frost. On the other hand, the back, which touched the sand, is a loathsome wreck, partly deprived of its feathers. The quills of the tail are bare barreled; a few whitened bones show, deprived of their muscles. The skin has turned into a dark leather, pierced with round holes like those of a sieve. It is all hideously ugly, but most instructive.

The wretched owl, with his shattered backbone, teaches us, first of all, that a temperature twelve degrees of frost does not endanger the existence of the bluebottle's germs. The worms were born without accident, despite the rude blast; they feasted copiously on extract of meat; then, growing big and fat, they descended into the earth by piercing round holes in the bird's skin. Their pupae must now be in the sand of the pan.

They are, in point of fact, and in such numbers that I have to resort to sifting in order to collect them. If I used the forceps, I should never have done sorting so great a quantity. The sand passes through the meshes of the sieve, the pupae remain above. To count them would wear out my patience. I measure them by the bushel, that is to say, with a thimble of which I know the holding capacity in pupae. The result of my calculation is not far short of nine hundred.

Does this family proceed from one mother? I am quite ready to admit it, so unlikely is it that the bluebottle, who is so rare inside our houses during the severe cold of winter, should be frequent enough outside to form into groups and to do business in common while an icy blast is raging. A belated specimen, the plaything of the north wind, and one alone must have deposited the burden of her ovaries on the owl's eyes. This laying of nine hundred eggs, an incomplete laying perhaps, bears witness to the mighty part played by the fly as a liquidator of corpses.

Before throwing away the screech owl treated by the worms, let us overcome our repugnance and give a glance inside the bird. We see a tortuous cavity, fenced in by nameless ruins. Muscles and bowels have disappeared, converted into broth and gradually consumed by the teeming throng. In every part, what was wet has become dry, what was solid muddy. In vain my forceps ransacks every nook and corner: it does not hit upon a single pupa. All the worms have emigrated, all, without exception. From first to last, they have forsaken the refuge of the corpse, so soft to their delicate skins; they have left the velvet for the hard ground. Is dryness necessary to them at this stage? They had it in the carcass, which was thoroughly drained. Would they protect themselves against the cold and rain? No shelter could suit them better than the thick quilt of the feathers, which has remained wholly undamaged on the belly, the breast and every part that was not in touch with the ground. It looks as though they had fled from comfort to seek a less kindly dwelling place. When the hour of transformation came, all left the owl, that most excellent lodging; all dived into the sand.

The exodus from the mortuary tabernacle was made through the round holes wherewith the skin is pierced. Those holes are the worms' work: of that there is no doubt; and yet we have lately seen the mothers refuse as a bed for their eggs any part whereat the flesh is protected by a skin of some thickness. The reason is the failure of the pepsin to act on epidermic substances. In the absence of liquefaction at such points, the nourishing gruel is unprocurable. On the other hand, the tiny worms are not able—or at least do not know how—to dig through the integument with their pair of guttural harpoons, to rend it and reach the liquefiable flesh. The newborn lack strength and, above all, purpose. But, as the time comes for descending into the earth, the worms, now powerful and suddenly versed in the necessary art, well know how to eat away patiently and clear themselves a passage. With the hooks of their spikes they dig, scratch and tear. Instinct has flashes of inspiration. What the animal did not know how to do at the start it learns without apprenticeship when the time comes to practice this or that industry. The maggot ripe for burial perforates a membranous obstacle which the grub intent upon its broth would not even have attempted to attack with either its pepsin or its grapnels.

Why does the worm quit the carcass, that capital shelter? Why does it go and take up its abode in the ground? As the leading disinfector of dead things, it works at the most important matter, the suppression of the infection; but it leaves a plentiful residuum, which does not yield to the reagents of its analytical chemistry. These remains have to disappear in their turn. After the fly, anatomists come hastening, who take up the dry relic, nibble skin, tendons and ligaments and scrape the bones clean.

The greatest expert in this work is the Dermestes beetle, an enthusiastic gnawer of animal remains. Sooner or later, he will come to the joint already exploited by the fly. Now what would happen if the pupae were there? The answer is obvious. The Dermestes, who loves hard food, would dig his teeth into the horny little kegs and demolish them at a bite. Even though he did not touch the contents, a live thing which he probably dislikes, he would at least test the flavor of that lifeless substance, the container. The future Fly would be lost, because her casing would be pierced. Even so, in the storerooms of our silk mills, a certain Dermestes (Dermestes vulpinus, FABR.) digs into the cocoons to attack the horny covering of the chrysalis.

The maggot foresees the danger and makes itself scarce before the other arrives. In what sort of memory does it house so much wisdom, indigent, headless creature that it is, for it is only by extension that we can give the name of head to the animal's pointed fore part? How did it learn that, to safeguard the pupa, it must desert the carcass and that, to safeguard the fly, it must not bury itself too far down?

To emerge from underground after the perfect insect is hatched, the bluebottle's device consists in disjointing her head into two movable halves, which, each distended with its great red eye, by turns separate and reunite. In the intervening space, a large, glassy hernia rises and disappears, disappears and rises. When the two move asunder, with one eye forced back to the right, the other to the left, it is as though the insect were splitting its brain pan in order to expel the contents. Then the hernia rises, blunt at the end and swollen into a great knob. Next, the forehead closes and the hernia retreats, leaving visible only a kind of shapeless muzzle. In short, a frontal pouch, with deep pulsations momentarily renewed, becomes the instrument of deliverance, the pestle wherewith the newly hatched bluebottle bruises the sand and causes it to crumble. Gradually the legs push the rubbish back and the insect advances so much toward the surface.

A hard task, this exhumation by dint of the blows of a cleft and palpitating head. Moreover, the exhausting effort has to be made at the moment of greatest weakness, when the insect leaves that protecting casket, its pupa. It emerges from it pale, flabby and unsightly, sorrily clad in the wings which, folded lengthwise and made shorter by their scalloped edge, only just cover the top of the back. Wildly bristling with hairs and colored ashen-gray, it is a piteous sight. The large set of wings, suitable for flight, will spread later. For the moment, it would only be in the way amid the obstacles to be passed through. Later also will come the faultless dress wherein the iridescent indigo-blue stands out against the severity of the black.

The frontal hernia that crumbles the sand with its impact has a tendency to make play for some time after the emergence from the ground. Take hold with the forceps of one of the hind legs of a newly released fly. Forthwith, the implement of the head begins to work, swelling and subsiding as energetically as a moment ago, when it had to make a hole in the sand. The insect, hampered in its movements as when it was underground, struggles as best it can against the only obstacle that it knows. With its heaving knob, it pounds the air even as but now it pounded the earthy barrier. In all unpleasant circumstances, its one resource is to cleave its head and produce its cranial hernia, which moves out and in, in and out. For nearly two hours, interspersed with halts due to fatigue, the little machine keeps throbbing in my forceps.

In the meantime, however, the desperate one is hardening her skin; she spreads wide the sail of her wings and dons her deep mourning of black and darkest blue. Then her eyes, warped sideways, come together and resume their normal position. The cleft forehead closes; the delivering blister goes in, never to show itself again. But there is one precaution to be taken first. With its front tarsi, the insect carefully brushes the bump about to disappear from view, lest grit should lodge in the cranium when the two halves of the head are joined for good.

The maggot is aware of the trials that await it when, as a fly, it will have to come up from under ground; it knows beforehand how difficult the ascent will be with the feeble instrument at its disposal, so difficult, in fact, as to become fatal should the journey be at all prolonged. It foresees the dangers ahead of it and averts them as well as it can. Gifted with two iron shod sticks in its throat, it can easily descend to such depths as it pleases. The need for greater quiet and a less trying temperature calls for the deepest possible home: the lower down it is, the better for the welfare of the worm and the pupa, on condition that descent be practicable. It is, perfectly; and yet, though free to obey its inspiration, the grub refrains. I rear it in a deep pan, full of fine, dry sand, easy to excavate. The interment never goes very far. About a hand's breadth is all that the most progressive digger ventures upon. Most of the interred remain nearer still to the surface. Here, under a thin layer of sand, the grub's skin hardens and becomes a coffin, a casket, wherein the transformation sleep is slept. A few weeks later, the buried one awakes, transfigured but weak, having naught wherewith to unearth herself but the throbbing hernia of her open forehead.

What the maggot denies itself it is open to me to realize, should I care to know the depth whence the fly is able to mount. I place fifteen bluebottle pupae, obtained in winter, at the bottom of a wide tube closed at one end. Above the pupae is a perpendicular column of fine, dry sand, the height of which varies in different tubes. April comes and the hatching begins.

A tube with six centimeters of sand, the shallowest of the columns under experiment, yields the best result. Of the fifteen subjects interred in the pupa stage, fourteen easily reach the surface when they become flies. Only one of them perishes, one who has not even attempted the ascent. With twelve centimeters of sand, four emerge. With twenty centimeters, two, no more. The other flies, jaded with their exertions, have died at a higher or lower stage of the road. Lastly, with yet another tube wherein the column of sand measured sixty centimeters, I obtained the liberation of only a single fly. The plucky creature must have had a hard struggle to mount from so great a depth, for the other fourteen did not even manage to burst the lid of their caskets.

I presume that the looseness of the sand and the consequent pressure in every direction, similar to that exercised by fluids, have a certain bearing on the difficulties of the exhumation. Two more tubes are prepared, but this time supplied with fresh mould, lightly heaped up, which has not the incoherence of sand, with the attendant drawback of pressure. Six centimeters of mould give me eight flies for fifteen pupae buried; twenty centimeters give me only one. There is less success than with the sandy column. My device has diminished the pressure, but, at the same time, increased the passive resistance. The sand falls of itself under the impact of the frontal rammer; the unyielding mould demands the cutting of a gallery. In fact, I perceive, on the road followed, a shaft which continues indefinitely such as it is. The fly has bored it with the temporary blister that throbs between her eyes.

In every medium, therefore, whether sand, mould or any earthy combination, great are the sufferings that attend the exhumation of the fly. And so the maggot shuns the depths which a desire for additional security might seem to recommend. The worm has its own prudence: foreseeing the dangers ahead, it refrains from making great descents that might promote the welfare of the moment. It neglects the present for the sake of the future.



CHAPTER XVI. A PARASITE OF THE MAGGOT

The dangers of the exhumation are not the only ones; the Bluebottle must be acquainted with others. Life, when all is said, is a knacker's yard wherein the devourer of today becomes the devoured of tomorrow; and the robber of the dead cannot fail to be robbed of her own life when the time comes. I know that she has one exterminator in the person of the tiny Saprinus beetle, a fisher of fat sausages on the edge of the pools formed by liquescent corpses. Here swarm in common the grubs of the greenbottle, the flesh fly and the bluebottle. The Saprinus draws them to him from the bank and gobbles them indiscriminately. They represent to him morsels of equal value.

This banquet can be observed only in the open country, under the rays of a hot sun. Saprini and greenbottles never enter our houses; the flesh fly visits us but discreetly, does not feel at home with us; the only one who comes fussing along is the bluebottle, who thus escapes the tribute due to the consumer of plump sausages. But, in the fields, where she readily lays her eggs upon any carcass that she finds, she, as well as the others, sees her vermin swept away by the gluttonous Saprinus.

In addition, graver disasters decimate her family, if, as I do not doubt, we can apply to the bluebottle what I have seen happen in the case of her rival, the flesh fly. So far, I have had no opportunity of actually perceiving with the first what I have to tell of the second; still, I do not hesitate to repeat about the one what observation has taught me about the other, for the larval analogies between the two flies are very close.

Here are the facts. I have gathered a number of pupae of the flesh fly in one of my vermin jars. Wishing to examine the pupa's hinder end, which is hollowed into a cup and scalloped into a coronet, I stave in one of the little barrels and force open the last segments with the point of my pocketknife. The horny keg does not contain what I expected to find: it is full of tiny grubs packed one atop the other with the same economy of space as anchovies in a bottle. Save for the skin, which has hardened into a brown shell, the substance of the maggot has disappeared, changed into a restless swarm.

There are thirty-five occupants. I replace them in their casket. The rest of my harvest, wherein, no doubt, are other pupae similarly stocked, is arranged in tubes that will easily show me what happens. The thing to discover is what genus of parasites the grubs enclosed belong to. But it is not difficult, without waiting for the hatching of the adults, to recognize their nature merely by their mode of life. They form part of the family of Chalcididae, who are microscopic ravagers of living entrails.

Not long ago, in winter, I took from the chrysalis of a great peacock moth four hundred and forty-nine parasites belonging to the same group. The whole substance of the future moth had disappeared, all but the nymphal wrapper, which was intact and formed a handsome Russia-leather wallet. The worm grubs were here heaped up and squeezed together to the point of sticking to one another. The hair pencil extracts them in bundles and cannot separate them without some difficulty. The holding capacity is strained to the utmost; the substance of the vanished Moth would not fill it better. That which died has been replaced by a living mass of equal dimensions, but subdivided. The price of this colony's existence is the conversion of the chrysalis into a sort of milk food of doubtful constitution. The enormous udder has been drained outright.

You shudder when you think of that budding flesh nibbled bit by bit by four or five hundred gormandizers; the horrified imagination refuses to picture the anguish suffered by the tortured wretch. But is there really any pain? We have leave to doubt it. Pain is a patent of nobility; it is more pronounced in proportion as the sufferer belongs to a higher order. In the lower ranks of animal life, it must be greatly reduced, perhaps even nil, especially when life, in the throes of evolution, has not yet acquired a stable equilibrium. The white of an egg is living matter, but endures the prick of a needle without a quiver. Would it not be the same with the chrysalis of the great peacock, dissected cell by cell by hundreds of infinitesimal anatomists? Would it not be the same with the pupa of the flesh fly? These are organisms put back into the crucible, reverting to the egg state for a second birth. There is reason to believe, therefore, that their destruction crumb by crumb is merciful.

Towards the end of August, the parasite of the flesh fly's grubs makes her appearance out of doors in the adult form. She is a Chalcidid, as I expected. She issues from the barrel through one or two little round holes which the prisoners have pierced with a patient tooth. I count some thirty to each pupa. There would not be enough room in the abode if the family were larger.

The imp is a slim and elegant creature, but oh, how small! She measures hardly two millimeters. Her garb is bronzed black, with pale legs and a heart shaped, pointed, slightly pedunculate abdomen, with never a trace of a probe for inoculating the eggs. The head is transversal, the width exceeding the length.

The male is only half the size of the female; he is also very much less numerous. Perhaps pairing is here, as we see elsewhere, a secondary matter from which it is possible to abstain, in part, without injuring the prospects of the race. Nevertheless, in the tube wherein I have housed the swarm, the few males lost among the crowd ardently woo the passing fair. There is much to be done outside, as long as the flesh fly's season lasts; things are urgent; and each pigmy hurries as fast as she can to take up her part as an exterminator.

How is the parasite's inroad into the flesh fly's pupae effected? Truth is always veiled in a certain mystery. The good fortune that secured me the ravaged pupa taught me nothing concerning the tactics of the ravager. I have never seen the Chalcidid explore the contents of my appliances; my attention was engaged elsewhere and nothing is so difficult to see as a thing not yet suspected. But, though direct observation be lacking, logic will tell us approximately what we want to know.

It is evident, to begin with, that the invasion cannot have been made through the sturdy amour of the pupae. This is too hard to be penetrated by the means at the pigmy's disposal. Naught but the delicate skin of the maggots lends itself to the introduction of the germs. An egg laying mother, therefore, appears, inspects the surface of the pool of sanies swarming with grubs, selects the one that suits her and perches on it; then, with the tip of her pointed abdomen, whence emerges, for an instant, a short probe kept hidden until then, she operates on the patient, perforating his paunch with a dexterous wound into which the germs are inserted. Probably, a number of pricks are administered, as the presence of thirty parasites seems to demand.

Anyway, the maggot's skin is pierced at either one point or many; and this happens while the grub is swimming in the pools formed by the putrid flesh. Having said this, we are faced with a question of serious interest. To set it forth necessitates a digression which seems to have nothing to do with the subject in hand and is nevertheless connected with it in the closest fashion. Without certain preliminaries, the remainder would be unintelligible. So now for the preliminaries.

I was in those days busy with the poison of the Languedocian scorpion and its action upon insects. To direct the sting toward this or the other part of the victim and moreover to regulate its emission would be absolutely impossible and also very dangerous, as long as the scorpions were allowed to act as they pleased. I wished to be able myself to choose the part to be wounded; I likewise wished to vary the dose of poison at will. How to set about it? The scorpion has no jarlike receptacle in which the venom is accumulated and stored, like that possessed, for instance, by the wasp and the bee. The last segment of the tail, gourd shaped and surmounted by the sting, contains only a powerful mass of muscles along which lie the delicate vessels that secrete the poison.

In default of a poison jar which I would have placed on one side and drawn upon at my convenience, I detach the last segment, forming the base of the sting. I obtain it from a dead and already withered scorpion. A watch glass serves as a basin. Here, I tear and crush the piece in a few drops of water and leave it to steep for four-and-twenty hours. The result is the liquid which I propose to use for the inoculation. If any poison remained in my animal's caudal gourd, there must be at least some traces of it in the infusion in the watch glass.

My hypodermic syringe is of the simplest. It consists of a little glass tube, tapering sharply at one end. By drawing in my breath, I fill it with the liquid to be tested; I expel the contents by blowing. Its point is almost as fine as a hair and enables me to regulate the dose to the degree which I want. A cubic millimeter is the usual charge. The injection has to be made at parts that are generally covered with horn. So as not to break the point of my fragile instrument, I prepare the way with a needle, with which I prick the victim at the spot required. I insert the tip of the loaded injector in the hole thus made and I blow. The thing is done in a moment, very neatly and in an orthodox fashion, favorable to delicate experiments. I am delighted with my modest apparatus.

I am equally delighted with the results. The scorpion himself, when wounding with his sting, in which the poison is not diluted as mine is in the watch glass, would not produce effects like those of my pricks. Here is something more brutal, producing more convulsion in the sufferer. The virus of my contriving excels the scorpion's.

The test is several times repeated, always with the same mixture, which, drying up by spontaneous evaporation, then made to serve again by the addition of a few drops of water, once more drained and once more moistened, does duty for an indefinite length of time. Instead of abating, the virulence increases. Moreover, the corpses of the insects operated upon undergo a curious change, unknown in my earlier observations. Then the suspicion comes to me that the actual poison of the scorpion does not enter into the matter at all. What I obtain with the end joint of the tail, with the gland at the base of the sting, I ought to obtain with any other part of the animal.

I crush in a few drops of water a joint of the tail taken from the front portion, far from the poison glands. After soaking it for twenty-four hours, I obtain a liquid whose effects are absolutely the same as those before, when I used the joint that bears the sting. I try again with the scorpion's claws, the contents of which consist solely of muscle. The results are just the same. The whole of the animal's body, therefore, no matter which fragment be submitted to the steeping process, yields the virus that so greatly pricks my curiosity.

Every part of the Spanish fly [Cantharis or blistering beetle], inside and out, is saturated with the blistering element; but there is nothing like this in the scorpion, who localizes his venom in his caudal gland and has none of it elsewhere. The cause of the effects which I observe is therefore connected with general properties which I ought to find in any insect, even the most harmless.

I consult Oryctes nasicornis, the peaceable rhinoceros beetle, on this subject. To get at the exact nature of the materials, instead of pulverizing the whole insect in a mortar, I use merely the muscular tissue obtained by scraping the inside of the dried Oryctes' corselet. Or else I extract the dry contents of the hind legs. I do the same with the desiccated corpses of the cockchafer, the Capricorn, or Cerambyx beetle, and the Cetonia, or rosechafer. Each of my gleanings, with a little water added, is left to soften for a couple of days in a watch glass and yields to the liquid whatever can be extracted from it by crushing and dissolving.

This time, we take a great step forward. All my preparations, without distinction, are horribly virulent. Let the reader judge. I select as my first patient the sacred beetle, Scarabaeus sacer, who thanks to his size and sturdiness, lends himself admirably to an experiment of this kind. I operate upon a dozen, in the corselet, on the breast, on the belly and, by preference, on one of the hind legs, far removed from the impressionable nervous centers. No matter what part my injector attacks, the effect produced is the same, or nearly. The insect falls as though struck by lightning. It lies on its back and wriggles its legs, especially the hind legs. If I set it on its feet again, I behold a sort of St. Vitus' dance. Scarabaeus lowers his head, arches his back, draws himself up on his twitching legs. He marks time with his feet on the ground, moves forward a little, moves as much backward, leans to the right, leans to the left, in wild disorder, incapable of keeping his balance or making progress. And this happens with sudden jerks and jolts, with a vigor no whit inferior to that of the animal in perfect health. It is a displacement of all the works, a storm that uproots the mutual relations of the muscles.

Seldom have I witnessed such sufferings, in my career as a cross-examiner of animals and, therefore, as a torturer. I should feel a scruple, did I not foresee that the grain of sand shifted today may one day help us by taking its place in the edifice of knowledge. Life is everywhere the same, in the Dung beetle's body as in man's. To consult it in the insect means consulting it in ourselves, means moving towards vistas which we cannot afford to neglect. That hope justifies my cruel studies, which, though apparently so puerile, are in reality worthy of serious consideration.

Of my dozen sufferers, some rapidly succumb, others linger for a few hours. They are all dead by tomorrow. I leave the corpses on the table, exposed to the air. Instead of drying and stiffening, like the asphyxiated insects intended for our collections, my patients, on the contrary, turn soft and slacken in the joints, notwithstanding the dryness of the surrounding air; they become disjointed and separate into loose pieces, which are easily removed.

The results are the same with the Capricorn, the cockchafer, the Procrustes [a large ground beetle], the Carabus [the true ground beetle, including the gold beetle]. In all of them there is a sudden break-up, followed by speedy death, a slackening of the joints and swift putrefaction. In a non-horny victim, the quick chemical changes of the tissues are even more striking. A Cetonia grub, which resists the scorpion's sting, even though repeatedly administered, dies in a very short time if I inject a tiny drop of my terrible fluid into any part of its body. Moreover, it turns very brown and, in a couple of days, becomes a mass of black putrescence.

The great peacock, that large moth who recks little of the scorpion's poison, is no more able to resist my inoculations than the sacred beetle and the others. I prick two in the belly, a male and a female. At first, they seem to bear the operation without distress. They grip the trellis work of the cage and hang without moving, as though indifferent. But soon the disease has them in its grip. What we see is not the tumultuous ending of the sacred beetle; it is the calm advent of death. With wings slackly quivering, softly they die and drop from the wires. Next day, both corpses are remarkably lax; the segments of the abdomen separate and gape at the least touch. Remove the hairs and you shall see that the skin, which was white, has turned brown and is changing to black. Corruption is quickly doing its work.

This would be a good opportunity to speak of bacteria and cultures. I shall do nothing of the sort. On the hazy borderland of the visible and the invisible, the microscope inspires me with suspicion. It so easily replaces the eye of reality by the eye of imagination; it is so ready to oblige the theorists with just what they want to see. Besides, supposing the microbe to be found, if that were possible, the question would be changed, not solved. For the problem of the collapse of the structure through the fact of a prick there would be substituted another no less obscure: how does the said microbe bring about that collapse? In what way does it go to work? Where lies its power?

Then what explanation shall I give of the facts which I have just set forth? Why, none, absolutely none, seeing that I do not know of any. As I am unable to do better, I will confine myself to a pair of comparisons or images, which may serve as a brief resting place for the mind on the dark billows of the unknown.

All of us, as children, have amused ourselves with the game of "card friars." A number of cards, as many as possible, are bent lengthwise into a semi-cylinder. They are placed on a table, one behind the other, in a winding row, the spaces in which are suitably disposed. The performance pleases the eye by its curved lines and its regular arrangement. It possesses order, which is a condition of all animated matter. You give a little tap to the first card. It falls and overturns the second, which, in the same way, topsy-turvies the third; and so on, right to the end of the row. In less than no time, the capsizing wave spreads and the handsome edifice is shattered. Order is succeeded by disorder, I might almost say, by death. What was needed thus to upset the procession of friars? A very, very slight first push, out of all proportion to the toppled mass.

Again, take a glass balloon containing a solution of alum supersaturated by heat. It is closed, during the process of boiling, with a cork and is then allowed to cool. The contents remain fluid and limpid for an indefinite period. Mobility is here represented by a faint semblance of life. Remove the cork and drop in a solid particle of alum, however infinitesimal. Suddenly, the liquid thickens into a solid lump and gives off heat. What has happened? This: crystallization has set in at the first contact of the particle of alum, the center of attraction; next, it has spread bit by bit, each solidified particle producing the solidification of those around. The impulse comes from an atom; the mass impelled is boundless. The very small has revolutionized the immense.

Of course, in the comparison between these two instances and the effects of my injections, the reader must see no more than a figure of speech, which, without explaining anything, tries to throw a glimmer of light upon it. The long procession of card friars is knocked down by the mere touch of the little finger to the first; the voluminous solution of alum suddenly turns solid under the influence of an invisible particle. In the same way, the victims of my operations succumb, thrown into convulsions by a tiny drop of insignificant size and harmless appearance.

Then what is there in that terrible liquid? First of all, there is water, inactive in itself and simply a vehicle of the active agent. If a proof were needed of its innocuousness, here is one: I inject into the thigh of any one of the sacred beetle's six legs a drop of pure water larger than that of the fatal inoculations. As soon as he is released, he makes off and trots about as nimbly as usual. He is quite firm on his legs. When put back to his pellet, he rolls it with the same zeal as before the experiment. My injection of water makes no difference to him.

What else is there in the mixture in my watch glasses? There is the disintegrated matter of the corpse, especially shreds of dried muscles. Do these substances yield certain soluble elements to water? Or are they simply reduced to a fine dust in the crushing? I will not decide this question, nor is it really of importance. The fact remains that the poison proceeds from those substances and from them alone. Animal matter, therefore, which has ceased to live is an agent of destruction within the organism. The dead cell kills the living cell; in the delicate statics of life, it is the grain of sand which, refusing its support, entails the collapse of the whole edifice.

In this connection, we may recall those dreadful dissecting room accidents. Through awkwardness, a student of anatomy pricks himself with his scalpel in the course of his work; or else, by inadvertence, he has an insignificant scratch on his hand. A cut which one would hardly notice, produced by the point of a pocket knife, a scratch of no account, from a thorn or otherwise, now becomes a mortal wound, if powerful antiseptics do not speedily remedy the ill. The scalpel is soiled by its contact with the flesh of the corpse; so are the hands. That is quite enough. The virus of corruption is introduced; and, if not treated in time, the wound proves fatal. The dead has killed the living. This also reminds us of the so-called carbuncle flies, the lancet of whose mouth parts, contaminated with the sanies of corpses, produces such terrible accidents.

My dealings as against insects are, when all is said, nothing but dissecting room wounds and carbuncle flies' stings. In addition to the gangrene that soon impairs and blackens the tissues, I obtain convulsions similar to those produced by the scorpion's sting. In its convulsive effects, the venomous fluid emitted by the sting bears a close resemblance to the muscular infusions with which I fill my injector. We are entitled, therefore, to ask ourselves if poisons, generally speaking, are not themselves a produce of demolition, a casting of the organism perpetually renewed, waste matter, in short, which, instead of being gradually expelled, is stored for purposes of attack and defense. The animal, in that case, would arm itself with its own refuse in the same way as it sometimes builds itself a home with its intestinal recrement. Nothing is wasted; life's detritus is used for self defense.

All things considered, my preparations are meat extracts. If I replace the flesh of the insect by that of another animal, the ox, for instance, shall I obtain the same results? Logic says yes; and logic is right. I dilute with a few drops of water a little Liebig's extract, that precious standby of the kitchen. I operate with this fluid on six Cetoniae or rosechafers, four in the grub stage, two in the adult stage. At first, the patients move about as usual. Next day, the two Cetoniae are dead. The larvae resist longer and do not die until the second day. All show the same relaxed muscles, the same blackened flesh, signs of putrefaction. It is probable, therefore, that, if injected into our own veins, the same fluid would likewise prove fatal. What is excellent in the digestive tubes would be appalling in the arteries. What is food in one case is poison in the other.

A Liebig's extract of a different kind, the broth in which the liquefier puddles, is of a virulence equal, if not superior, to that of my products. All those operated upon, Capricorns, sacred beetles, ground beetles, die in convulsions. This brings us back, after a long way round, to our starting point, the maggot of the flesh fly. Can the worm, constantly floundering in the sanies of a carcass, be itself in danger of inoculation by that whereon it grows fat? I dare not rely upon experiments conducted by myself: my clumsy implements and my shaky hand make me fear that, with subjects so small and delicate, I might inflict deep wounds which of themselves would bring about death.

Fortunately, I have a collaborator of incomparable skill in the parasitic Chalcidid. Let us apply to her. To introduce her germs, she has perforated the maggot's paunch, has even done so several times over. The holes are extremely small, but the poison all around is excessively subtle and has thus been able, in certain cases, to penetrate. Now what has happened? The pupae, all from the same apparatus, are numerous. They can be divided into three not very unequal classes, according to the results supplied. Some give me the adult flesh fly, others the parasite. The rest, nearly a third, give me nothing, neither this year nor next.

In the first two cases, things have taken their normal course: the grub has developed into a fly, or else the parasite has devoured the grub. In the third case, an accident has occurred. I open the barren pupae. They are coated inside with a dark glaze, the remains of the dead maggot converted into black rottenness. The grub, therefore, has undergone inoculation by the virus through the fine openings effected by the Chalcidid. The skin has had time to harden into a shell; but it was too late, the tissues being already infected.

There you see it: in its broth of putrefaction, the worm is exposed to grave dangers. Now there is a need for maggots in this world, for maggots many and voracious, to purge the soil as quickly as possible of death's impurities. Linnaeus tells us that 'Tres muscae consumunt cadaver equi aeque cito ac leo.' [Three flies consume the carcass of a horse as quickly as a lion could do it.] There is no exaggeration about the statement. Yes, of a certainty, the offspring of the flesh fly and the bluebottle are expeditious workers. They swarm in a heap, always seeking, always snuffling with their pointed mouths. In those tumultuous crowds, mutual scratches would be inevitable if the worms, like the other flesh eaters, possessed mandibles, jaws, clippers adapted for cutting, tearing and chopping; and those scratches, poisoned by the dreadful gruel lapping them, would all be fatal.

How are the worms protected in their horrible work yard? They do not eat: they drink their fill; by means of a pepsin which they disgorge, they first turn their foodstuffs into soup; they practice a strange and exceptional art of feeding, wherein those dangerous carving implements, the scalpels with their dissecting room perils, are superfluous. Here ends, for the present, the little that I know or suspect of the maggot, the sanitary inspector in the service of the public health.



CHAPTER XVII. RECOLLECTIONS OF CHILDHOOD

Almost as much as insects and birds—the former so dear to the child, who loves to rear his cockchafers and rose beetles on a bed of hawthorn in a box pierced with holes; the latter an irresistible temptation, with their nests and their eggs and their little ones opening tiny yellow beaks—the mushroom early won my heart with its varied shapes and colors. I can still see myself as an innocent small boy sporting my first braces and beginning to know my way through the cabalistic mazes of my reading book, I see myself in ecstasy before the first bird's nest found and the first mushroom gathered. Let us relate these grave events. Old age loves to meditate the past.

O happy days when curiosity awakens and frees us from the limbo of unconsciousness, your distant memory makes me live my best years over again. Disturbed at its siesta by some wayfarer, the partridge's young brood hastily disperses. Each pretty little ball of down scurries off and disappears in the brushwood; but, when quiet is restored, at the first summoning note they all return under the mother's wing. Even so, recalled by memory, do my recollections of childhood return, those other fledglings which have lost so many of their feathers on the brambles of life. Some, which have hardly come out of the bushes, have aching heads and tottering steps; some are missing, stifled in some dark corner of the thicket; some remain in their full freshness. Now of those which have escaped the clutches of time the liveliest are the first-born. For them the soft wax of childish memory has been converted into enduring bronze.

On that day, wealthy and leisured, with an apple for my lunch and all my time to myself, I decided to visit the brow of the neighboring hill, hitherto looked upon as the boundary of the world. Right at the top is a row of trees which, turning their backs to the wind, bend and toss about as though to uproot themselves and take to flight. How often, from the little window in my home, have I not seen them bowing their heads in stormy weather; how often have I not watched them writhing like madmen amid the snow dust which the north wind's broom raises and smoothes along the hillside! 'What are they doing up there, those desolate trees? I am interested in their supple backs, today still and upright against the blue of the sky, tomorrow shaken when the clouds pass overhead. I am gladdened by their calmness; I am distressed by their terrified gestures. They are my friends. I have them before my eyes at every hour of the day. In the morning, the sun rises behind their transparent screen and ascends in its glory. Where does it come from? I am going to climb up there and perhaps I shall find out.

I mount the slope. It is a lean grass sward close-cropped by the sheep. It has no bushes, fertile in rents and tears, for which I should have to answer on returning home, nor any rocks, the scaling of which involves like dangers; nothing but large, flat stones, scattered here and there. I. have only to go straight on, over smooth ground. But the sward is as steep as a sloping roof. It is long, ever so long; and my legs are very short. From time to time, I look up. My friends, the trees on the hilltop, seem to be no nearer. Cheerily, sonny! Scramble away!

What is this at my feet? A lovely bird has flown from its hiding place under the eaves of a big stone. Bless us, here's a nest made of hair and fine straw! It's the first I have ever found, the first of the joys which the birds are to bring me. And in this nest are six eggs, laid prettily side by side; and those eggs are a magnificent blue, as though steeped in a dye of celestial azure. Overpowered with happiness, I lie down on the grass and stare.

Meanwhile, the mother, with a little clap of her gullet—'Tack! Tack!'—flies anxiously from stone to stone, not far from the intruder. My age knows no pity, is still too barbarous to understand maternal anguish. A plan is running in my head, a plan worthy of a little beast of prey. I will come back in a fortnight and collect the nestlings before they can fly away. In the meantime, I will just take one of those pretty blue eggs, only one, as a trophy. Lest it should be crushed, I place the fragile thing on a little moss in the scoop of my hand. Let him cast a stone at me that has not, in his childhood, known the rapture of finding his first nest.

My delicate burden, which would be ruined by a false step, makes me give up the remainder of the climb. Some other day I shall see the trees on the hilltop over which the sun rises. I go down the slope again. At the bottom, I meet the parish priest's curate reading his breviary as he takes his walk. He sees me coming solemnly along, like a relic bearer; he catches sight of my hand hiding something behind my back: 'What have you there, my boy?' he asks.