of this domestic economy. The bill of fare of fossil animals, though written in characters less distinct and complete, can still be very frequently read in the substance of their coprolites. We do not despair even to find some day the fishes and the crustaceans which were chased by the plesiosaurs and the ichthyosaurs, and to discover some parasitic worms which had entered with them into the convolutions of the intestines of the saurians.

Naturalists have not always studied with sufficient care the correspondence which exists between the animal and its food, although it supplies the student with information of a very valuable kind. In fact, every organized body, whether conferva or moss, insect or mammal, becomes the prey of some animal; every organic substance, sap or blood, horn or feather, flesh or bone, disappears under the teeth

of some one or other of these; and to each kind of débris correspond the instruments suitable for its assimilation. These primary relations between living beings and their alimentary regimen call forth the activity of every species.

We find, on closer examination, more than one analogy between the animal world and human society; and without much careful scrutiny, we may say that there is no social position which has not (if I may dare to use the expression) its counterpart among the lower animals.

The greater part of these live peaceably on the fruit of their labour, and carry on a trade by which they gain their livelihood; but by the side of these honest workers we find also some miserable wretches who cannot do without the assistance of their neighbours, and who establish themselves, some as parasites in their organs, others as uninvited guests, by the side of the booty which they have gained.

Some years ago, one of our learned and ingenious colleagues at the University of Utrecht, Professor Harting, wrote a charming book on the industry of animals, and demonstrated that almost every trade is known in the animal kingdom. We find among them miners, masons, carpenters, paper manufacturers, weavers, and we may even say lace-makers, all of whom work first for themselves, and afterwards for their progeny. Some dig the earth, construct and support vaults, clear away useless earth, and consolidate their works, like miners; others build huts or palaces according to all the rules of architecture; others know intuitively all the secrets of the manufacturers of paper, cardboard, woollen stuffs or lace; and their productions need not fear comparison with

the point-lace of Mechlin or of Brussels. Who has not admired the ingenious construction of the beehive or of the ant-hill, or the delicate and marvellous structure of the spider’s web? The perfection of some of these works is so great and so generally appreciated, that when the astronomer requires for his telescope a slender and delicate thread, he applies to a living shop, to a simple spider. When the naturalist wishes to test the comparative excellence of his microscope, or requires a micrometer for infinitely little objects, he consults, not a millimetre, divided and subdivided into a hundred or a thousand parts, but the simple carapace of a diatom, so small and indistinct that it is necessary to place a hundred of them side by side to render them visible to the naked eye: and still more, the best microscopes do not always reveal all the delicacy of the designs which decorate these Lilliputian frustules. Mons. H. Ph. Adan has lately shown, with an artist’s talent, the infinite beauties which the microscope reveals in this invisible world.

To whom do the manufacturers of Verviers or of Lyons, of Ghent or of Manchester, apply for their raw materials? Either to an animal or a plant; and even up to the present time we have had sufficient modesty not to have sought to imitate either wool or cotton. Yet these animal manufacturers carry on their operations every day under our eyes, the doors wide open to everybody, and none of them is as yet marked with the trite expression, “No admittance.”

“The beau-ideal which we place before us in the arts of spinning and weaving,” said an inhabitant of the South to Michelet, “is the beautiful

hair of a woman: the softest wool, the finest cotton, is very far from realizing it.” The Southerner seemed to forget that this soft wool, as well as this fine cotton, was not the product of our manufacturers any more than the woman’s hair.

Were these animal machines to sustain injury, or even to be idle for a certain time, we should be reduced to have nothing wherewith to cover our shoulders: the fine lady would have neither Cashmere shawl, silk, nor velvet in her wardrobe; we should have neither flannel nor cloth to make our clothes; the herdsman even would not have his goat’s skin to protect him from the inclemency of the season. Thanks to the animal which gives us his flesh and his fleece, we are able to leave the southern regions, to brave the rigour of other climes, and establish ourselves side by side with the reindeer and the narwhal, in the midst of eternal snow.

We have our science and our steam-engines, of which we are justly proud; the animals have only their simple instinct to enable them to fabricate their marvellous tissues, and yet they succeed better than ourselves. The so-called blind forces of nature produce thread, the use of which the genius of man seeks in vain to supersede; and we do not even dream of entering into competition with these living machines which we daily crush under our feet.

All these occupations are openly carried on; and if there are some which are honest, it may be said that there are others which deserve another character. In the ancient as well as the new world, more than one animal resembles somewhat the sharper leading the life of a great

nobleman; and it is not rare to find, by the side of the humble pickpocket, the audacious brigand of the high road, who lives solely on blood and carnage. A great proportion of these creatures always escape, either by cunning, by audacity, or by superior villainy, from social retribution.

But side by side with these independent existences, there are a certain number which, without being parasites, cannot live without assistance, and which demand from their neighbours, sometimes only a resting-place in order to fish by their side, sometimes a place at their table, that they may partake with them of their daily food; we find some every day which used to be considered parasites, yet which by no means live at the expense of their hosts.

When a copepod crustacean instals himself in the pantry of an ascidian, and filches from him some dainty morsel, as it passes by; when a benevolent animal renders some service to his neighbour, either by keeping his back clean, or removing detritus which clogs certain organs, this crustacean or this animal is no more a parasite than is he who cowers by the side of a vigilant and skilful neighbour, quietly takes his siesta, and is contented with the fragments which fall from the jaws of his companion. We may say the same thing of the fish which, through idleness, attaches itself, like the remora, to a neighbour who swims well, and fishes by his side without fatiguing his own fins.

The services of many of these are rewarded either in protection or in kind, and mutuality can well be exercised at the same time as hospitality.

Those creatures which merit the name of parasites feed at the expense

of a neighbour,