WHILE great pains are devoted to the breeding of horses, cattle, and sheep among animals, to that of several kinds of birds, and to the propagation of fish, the flea has been left to shift for itself, and has managed to thrive. Whether the flea was, in the first place, an inhabitant of all terrestrial portions of the globe, or whether, starting from a common centre, it speedily spread itself over the earth, is a point which has not been decided; but the habits of the flea admirably fit him as a traveller; he is a natural stowaway, and being able to subsist for a long time without nourishment, he can perform the longest journeys without inconvenience among the other belongings of the traveller to whom he has temporarily attached himself. At the same time, he manages if possible to become the personal attendant and companion of his fellow-voyager for the time being, and to carry, as it were, his food as well as his lodging with him. So constant are these migrations, so assiduous are fleas in their attachment to man, that it is computed that even if they started as distinct nationalities constant intermixture must have so leavened them that the whole race is now practically homogeneous, and speak a language common to all. Although partial to comfort, and occasionally taking up his abode in the warm and cosy dwellings of the rich, the flea is by no means particular, and makes himself equally at home in the tent of the Arab, the hovel of the Mexican, the snowhouse of the Esquimaux, the cottage of the Spaniard, or the hut of the Persian. He will exist in the sand, and wait patiently for the chance passage of something he can devour; but his preferences lie in the direction of crowded tenements, and the dirtier and more untidy the better. The flea rivals the dog in his affection for man; he will cling to him to the last, and anger and even execrations do not shake his attachment. He is of a lively disposition, and there is nothing that he enjoys more than being hunted, entering thoroughly into the spirit of the thing, showing himself occasionally to inspire his eager pursuer with hope, and then disappearing into air. With other creatures it is generally safe to infer that they will leap forward. The flea, however, is bound by no rules, and can spring backward, forward, or sideways with equal ease. The power of his hind legs is prodigious, and it is well for man that he prefers to remain small, for a flea who took into his head to grow even as large as a cat would be a very formidable creature. It has been calculated by an American man of science that if the mule had the same proportionate power in his hind legs as has the flea, he could kick an ordinary-sized man 33 miles 1004 yards and 21 inches. Mankind has therefore good reason for congratulating itself upon the fact that the flea has not, in the course of his career, had any ambition in the direction of size, and that the smallest and most active only survived in the struggle for existence.

The habits of a flea have not been sufficiently investigated to enable us to state with certainty whether he uses his hind legs as weapons in his contests with other insects; but it is to be presumed that he does so, for why otherwise should Nature have endowed him with so much power in these limbs? If the ordinary mode of progression of the flea were, like that of the grasshopper, by a succession of springs, the prodigious size of his hind legs would be accountable; but, upon the contrary, the flea is essentially a runner, and the speed with which he can make his way through the thick fur of a cat or the hair of a dog is wonderful. It does not appear, indeed, that he ever does take to jumping except when inclined to drive human beings on the search for him into a state of frenzy.

As it cannot be reasonably supposed that Nature gifted the flea with such abnormal saltatory powers merely that he should be a cause of bad language among the human kind, some other explanation must be sought for. The Darwinian theory, that living creatures develop by the survival of the fittest such powers as may be most useful to them, fails altogether here, unless it be supposed that the flea’s legs have developed only since he made his acquaintance with man. In the earlier periods of his history, when he lived in the hair or fur of animals, he could have had no occasion whatever to jump. Unfortunately, the early historians, in dealing with the flea, are silent as to the length of his leaps, and we have, therefore, no means of estimating the rate at which he has progressed in this accomplishment during the last two or three thousand years. Yet, doubtless, he was present at the Siege of Troy, dwelt in the tent of Achilles, and stirred Ulysses to occasional wrath; it would have been well, then, had Homer turned for a moment from recording the struggles of the Greeks and Trojans, and given us a little solid information respecting the flea of those days.

Although abundant everywhere, he is found to be most prolific and numerous in the East. Upon this point all travellers are agreed. Some put it down to the fact that he loves heat; others to his partiality for dirt; while others again go back to the days of the Flood for the explanation. While other animals went into the Ark in pairs, it is morally certain that the flea went in his thousands; and as the four men in charge of all the animals can have had but little time to attend to the flea, and as, so far as is known, insecticide powder was not invented in those days, the flea doubtless multiplied prodigiously during the long voyage. Not knowing what was going on outside, the colony would be taken by surprise when the animals suddenly quitted the Ark; and vast numbers must have been left behind; these must, after the departure of man and the animals from the mountain on which the Ark rested, have shifted for themselves as they best could. Some would have early started on their travels, others would have clung to the Ark until it fell to pieces; but in time, at any rate, they must have scattered over the East, and there, being poor travellers except when carried, they and their descendants have remained ever since. It would be rash to say that this is the only plausible theory. Doubtless others can be advanced; but, taking it altogether, it certainly appears the most probable explanation of the abundance of the flea in Asia, and it may be said in Russia also, and other contiguous countries.

The flea is capable of being tamed, and of affording amusement to man by various little tricks. The first step in the process is to restrain his natural inclination to jump. This is done by placing him in a low, flat box with a glass lid. The flea, supposing that he has an open space overhead, jumps, strikes the glass with great violence, and falls half-stunned. This discourages him, but, unable to account for the phenomenon, he tries again and again, until at last, after some days, he arrives at the conclusion that there is something altogether wrong with the atmosphere, and that jumping must be abandoned. After this the rest is easy. He can be taught to drag a little carriage, to sit on the box, to fire a tiny cannon, or to perform other feats. He never, however, recovers thoroughly from the effect of his terrible blows against the glass. His heart and his spirit appear to be alike broken. Like a caged eagle he mopes out his life, and seldom lives more than a month or six weeks after his education is completed.

His is, in fact, the true gipsy spirit. Free, he will make himself happy under any circumstances, and although he may have his preferences, can get on anywhere. He loves the young and the tender, but does not despise age. Free, he is joyous, lively, and daring: a captive and chained, he pines and dies. It is a pity that no one will do for him what Sir John Lubbock has done for the ant. Such an investigator would no doubt be able to rehabilitate the flea in public estimation. Although he may be forced to live in dirty places, he is himself perfectly clean, taking great pains to clean himself with his hind legs, as does the fly. He is clad in shining armour, which is wonderfully tough and strong; his eyes are lively and prominent. Even in his most joyous moments he is never noisy; his attentions to man are unwearied, and the gentle irritation thereby caused affords means of occupation and excitement to the lazy mendicant, the indolent native of the South, and the contemplative Oriental, and rouses them from the lethargy in which they might otherwise sink. Fully and properly understood, the flea might take high rank among the benefactors of man.