[[p. 182]] These Essays, written nearly a century ago, seem to have been intended chiefly as an answer to the doctrines of those French philosophers who maintained that animals were merely animated machines, or, as it was expressed by Buffon, that "the animal is a purely material being, which neither thinks nor reflects, but which nevertheless acts," and that "the determining principle of the animal's actions proceeds from a purely mechanical influence, absolutely dependent upon its organisation." Our author, on the contrary, maintains that the mental faculties of animals are strictly comparable with those of man; that they remember, combine, and reflect; that they are capable of self-improvement; and even that they possess a true language fully adapted to their needs. To support his views he gives what we may term a generalised life history of several animals, such as the wolf, fox, stag, fallow-deer, and roebuck, which his position of Ranger of Versailles and Marly gave him ample opportunities of studying. The chief fault of these interesting sketches is, that they detail hardly any [[p. 183]] of the special observation on which the generalised statements are founded. We are, therefore, unable to tell how much is fact and how much inference; and, what is probably the result of careful life-long observation fails to produce that effect of reality which a more direct narrative style would have given to it. In a few cases, however, he gives us actual observations; as when he proves that animals can count, by stating the fact that in order to destroy crows, which were destructive to game, a hut was made at the foot of a tree where there was a nest, in order to shoot the old birds when they returned to their young. It was found, however, that after the first time the man was always watched into the hut, and the crows would not return till he had left it or till night. To deceive them two men went to the door of the watch-house, one entering and the other passing on, but the crows would not come. The next day three went and two passed on, but still with no effect; and it was not till five or six went and all but one passed on, that they were deceived, being unable to count so many.

    M. Leroy appears to reject altogether what is commonly termed Instinct, maintaining that the word should be applied only to those acts which are the direct consequences of organisation, such as the grazing of the stag, or the flesh-eating of the fox; but not to the expedients to which those animals resort in the gratification of their natural wants, which are due to sensation, observation, memory, and experience. To the objection that many animals perform complex operations perfectly well without experience, and always in the same manner, he replies that in many cases the fact is not so. He maintains, for instance, that there is a distinctly perceptible inferiority in the nests made by young birds, thus anticipating the observation of the American Wilson; and further remarks that the best constructed nests are formed by birds whose young remain a long time in them, and thus have more opportunity of seeing how they are made. He says that the nests of young birds are ill-made and badly situated; and that the defects of these first constructions are remedied in time, when their builders have been instructed by their sense of the inconveniences they have endured. He maintains that nests of the same species of bird differ as much as human dwellings, and that of a hundred swallows' nests no two are exactly alike; and he imputes to want of long-continued observation our failure to discover improvement in them; a want which curiously enough, has been remedied by M. Pouchet, who has found a decided improvement in the nests of swallows at Rouen during his own lifetime. Our author has also some excellent remarks on hereditary habit, as strikingly shown in the case of many of our sporting dogs, and which, he believes, in wild animals is often mistaken for instinct; and he concludes that "It is possible that the actions which we see performed by some animals, independently of the teachings of experience, are the fruit of a knowledge of very ancient date, and that in former times a thousand trials, attended with more or less success, have finally led to the attainment of the degree of perfection which we see manifested in some of their works at the present day."

    The migrations of birds, also, he maintains are the result of no blind instinct, but of instruction handed down from generation to generation. He says, "Let us take the swallows as an example which every one can observe. In the first place, their departure is always preceded by assemblages, the frequency and duration of which can leave no doubt that their object is to effect all the necessary preparations for a voyage undertaken by creatures who have the faculty of sensibility, and of understanding one another, and who are united for a common purpose. The incessant and varied twittering which reigns in these assemblies, clearly indicates communications and orders, indispensable for the numerous offspring of the year. They must stand in need of preliminary instruction, constantly repeated, to prepare them for the great event. Frequent trials of flight are no less indispensable, and are often followed by a repetition of previous lessons, which makes our roofs and chimneys ring again. Assemblies of men who should speak a foreign language could not give more evident signs of a similar project. But there is a more convincing proof than this analogy that these migrations are not the result of a blind and mechanical inclination. When, at the time fixed upon for the flight, which cannot, owing to weather, be retarded without compromising the welfare of the whole species, some, and even a large number of individuals, are too young to follow the rest, they are left behind and remain in the country. But it is in vain that they reach maturity; the supposed attraction towards a certain region does not affect them, or too slightly to enable them to gratify it. They perish, the victims of their ignorance, and of the tardy birth which made them unable to follow their parents."

    The letters on Man, which are curiously mixed up with those on animals, are neither so interesting nor so well reasoned. Their object is mainly to deduce the complex phenomena of human existence from the two principles of "the love of ease" and "ennui," which being antagonistic, lead men to all kinds of expedients to secure the one or escape from the other. These, with sympathy, which he considers, the pre-eminently human emotion, are made to explain most of the facts of man's mental nature. The work is written throughout in a pleasing and simple style, and exhibits to us a loving student of nature who observed and thought for himself, and who, in many of his conceptions, was far in advance of the great philosophers of the last century, among whom he lived.