Jean Henri Fabre

Little Pests

"T HE chief constituent of cheese, as we have already seen, is casein, which is separated from the rest of the milk by the action of rennet. But casein alone would make very poor cheese, and therefore it is customary to add more or less cream to it and thus furnish a cheese of greater richness and savor. The amount of cream added determines in general the richness and palatability of the cheese, and thus innumerable grades and varieties of this article of food are offered for our selection; yet they all owe their origin to the one substance, milk.

"Kept too long, as I have told you before, all cheeses, some earlier, others later, become moldy, first on the outside, then on the inside, the mold being at the outset of a yellowish white, afterward blue or greenish, and finally brick-red. At the same time the substance of the cheese decays and acquires a repulsive odor and a flavor so acrid as to make the lips smart. Henceforth the cheese is nothing but a putrid mass which must be thrown away. Deterioration is more or less rapid according to the softness or hardness of the cheese and its permeability by the air. To make cheese keep well, therefore, it must be dried thoroughly and reduced to compactness by strong pressure. Certain varieties of Dutch cheese, remarkable for their durability, are so hard and compact that sometimes, before they can be eaten, they have to be broken up with a hammer and softened by wrapping in linen soaked in white wine. But, hard though they are, these cheeses are valued for seasoning, for which purpose they are first reduced to powder on a grater; and they are also serviceable in the provisioning of ships for long voyages.

"Mold and decay are not the only enemies of cheese; there are also certain little creatures, mites and worms, that invade its substance and establish themselves there, defiling the cheese by their presence and gnawing it away, little by little. The cheese mite, or acarus domesticus,  as it is called by the learned, is a tiny creature hardly visible to the naked eye, with a body all bristling with stiff hairs and supported by eight short legs. Burrowing with its pointed head into the soft cheese, it lives there in colonies of a membership past counting, protected by the rind and taking shelter in the crevices. Assembled in mass, these animalcules look like so much dust, though on closer inspection it is seen to be animate dust, moving and swarming, and resolvable into a prodigious number of extremely small lice. If these mites are allowed to multiply at their own sweet will, the cheese gradually crumbles to dust. To ward off their inroads cheeses should be occasionally scrubbed with a stiff brush and the shelves holding them washed with boiling water. Cheese already attacked should first be well brushed and then rubbed with oil, which kills the mites. A more energetic procedure consists in subjecting the cheese to the fumes of burning sulphur in a closed box or chest. The sulphurous gas kills the animalcules without in the least impairing the quality of the cheese."

"And what about the worms you spoke of?" asked Claire.

"They are even more to be feared than the mites. What could be more disgusting than a piece of cheese promenading, so to speak, across one's plate, borne on the backs of these horrid creatures?"

"Sometimes they are so numerous," remarked Marie, "that the substance of the cheese seems changed into vermin. It must be the decay that turns the cheese into mites and worms."

"No, indeed, my child; never in all the world does decay engender vermin. Cheese-mites and cheese-worms come from eggs laid by other mites and by the flies into which the worms are finally changed just as caterpillars are changed into butterflies."

"Then the vermin that we see swarming in all sorts of decay does not really come from that decay?"

"Surely not. The decay feeds the vermin, but never brings it into being. It comes from eggs laid by various insects, especially by flies that are attracted from a distance by the smell of decay. Thus cheese-worms finally turn into flies of various kinds whose lifetime is spent in the open air, often amid the flowers. When the time comes for laying their eggs these flies, guided as they are by the sense of smell, know very well how to find our supplies of cheese. There they deposit their eggs, each of which becomes a little worm which later turns into a fly."

"How about the worms we find in fruit?" asked Jules. "Do they come from eggs?"

"Yes, all worms, wherever they may be found, owe their origin to eggs laid by insects; and never, bear in mind, are they produced directly by decay. Let me give you a few examples.

"Who is not familiar with the cherry-worm? The cherry itself may be of fine appearance, plump, dark purple, bursting with juice. Just as you are about to put it to your lips you feel a certain softness near the stem; and your suspicions are aroused. You open the cherry. Pah! A disgusting worm swims in the decaying pulp. That is enough. Those fine cherries tempt you no more. Well, that worm, if left undisturbed, will turn into a beautiful black fly, the cherry ortalis,  with diaphanous wings crossed by four dark bands. The insect lays its eggs on cherries still green, one on each. No sooner is it hatched than the worm bores a hole through the pulp and installs itself next to the stone. This orifice is very small and, more than that, it soon closes up, so that the fruit inhabited by the worm looks sound. The worm's presence does not interfere with the growth and ripening of the cherry, a fortunate circumstance for the worm, which is thus allowed to gorge itself with the juicy sweet pulp. When the cherry is ripe the worm is also fully developed, after which it leaves the fruit and drops to the ground, where it digs itself in and waits for the next May, when it will turn into a fly, lay its eggs on the young cherries, and die."

"Now I understand," said Marie, "how the worm gets into the cherry. I had always supposed it came in some way from the decaying pulp of the fruit."

"I will next show you," continued Uncle Paul, "a picture of the insect that in its worm state eats nuts. It is called the nut-weevil with its long, pointed beak it pierces a hole in the tender shell of the young fruit, and at the bottom of this hole, in contact with the nut-meat, it deposits an egg which in a few days hatches a tiny worm. As this worm eats but very little the nut continues to grow and the nut-meat ripens; but the gnawing goes on. Some time in August the stock of food comes to an end and the worm-eaten nut falls to the ground. The weevil itself, its jaws now robust, bores a round hole in the empty shell and abandons its early home to burrow into the ground, where its transformation takes place and the worm becomes a perfect insect."

Nut-Weevil

"I often find," said Emile, "under the hazelnut trees in the garden, nuts that look all right at first, only each one has a little hole in it and no meat inside."

"The meat has been devoured by the nut-weevil, and the round hole is the door by which the creature made its exit."

"Sometimes," said Claire, "when I crack nuts with my teeth, I bite into something bitter and soft."

"That," returned her uncle, "is the worm of the nut-weevil, crushed by your teeth."

"Pah! The nasty thing!" she exclaimed.

"And what about the worms we often find in apples and pears?" asked Marie.

"Those are what are commonly called apple-worms, or in learned language, Pyralidæ.  the moth has wings in two pairs, the upper being of an ash-gray marbled crosswise with brown and adorned at the wing-tips with a large red spot surrounded by a golden-red band; the lower of a uniform brown. As soon as the fruit begins to form the insect lays an egg in the blossom-end of the apple or pear, either fruit being alike acceptable. The tiny worm that hatches out, no bigger than a hair, bores into the fruit and establishes itself near the seeds. The little orifice by which it entered soon heals over so that the apple or pear appears sound for some time.

Apple-Worm

"Meanwhile the worm goes on growing in the lap of plenty. It makes a hole communicating with the outside, to admit fresh air and insure the ventilation essential to the sanitary condition of its abode with all its encumbrance of rubbish and excrement. By this tunnel bored through the pulp of the fruit till the outside is reached the worm both receives fresh air and from time to time ejects, in the form of reddish wormhole-dust, the pulp gnawed and digested. Apples and pears thus infested do not cease to grow; on the contrary they mature even earlier than the others, but it is a sickly maturity, and hastens the fall of the fruit. The worm in the fallen apple or pear leaves its domicile by the exit already prepared and withdraws into a crevice in the tree's bark, or sometimes into the ground, where it fashions for itself a cocoon of silk mingled with bits of wood or dead leaves; and the next year it turns into a moth, at the season that brings forth the young apples and pears in which are to be laid the eggs for a new generation of worms."