The opinion advanced by the Count de Buffon,[7] is 1. That the animals common both to the old and new world are smaller in the latter. 2. That those peculiar to the new are on a smaller scale. 3. That those which have been domesticated in both have degenerated in America; and 4. That on the whole it exhibits fewer species. And the reason he thinks is, that the heats of America are less; that more waters are spread over its surface by nature, and fewer of these drained off by the hand of man. In other words, that _heat_ is friendly, and _moisture_ adverse to the production and development of large quadrupeds. I will not meet this hypothesis on its first doubtful ground, whether the climate of America be comparatively more humid? Because we are not furnished with observations sufficient to decide this question. And though, till it be decided, we are as free to deny as others are to affirm the fact, yet for a moment let it be supposed. The hypothesis, after this supposition, proceeds to another; that _moisture_ is unfriendly to animal growth. The truth of this is inscrutable to us by reasonings _à priori_. Nature has hidden from us her _modus agendi_. Our only appeal on such questions is to experience; and I think that experience is against the supposition. It is by the assistance of _heat_ and _moisture_ that vegetables are elaborated from the elements of earth, air, water, and fire. We accordingly see the more humid climates produce the greater quantity of vegetables. Vegetables are mediately or immediately the food of every animal; and in proportion to the quantity of food, we see animals not only multiplied in their numbers, but improved in their bulk, as far as the laws of their nature will admit. Of this opinion is the Count de Buffon himself in another part of his work;[8] "en general il paroit ques les pays un peu _froids_ conviennent mieux á nos boeufs que les pays chauds, et qu'ils sont d'autant plus gross et plus grands que le climat est plus _humide_ et plus abondans en paturages. Les boeufs de Danemarck, de la Podolie, de l'Ulkraine et de la Tartarie qu habitent les Calmouques sont les plus grands de tous." Here then a race of animals, and one of the largest too, has been increased in its dimensions by _cold_ and _moisture_, in direct opposition to the hypothesis, which supposes that these two circumstances diminish animal bulk, and that it is their contraries _heat_ and _dryness_ which enlarge it. But when we appeal to experience we are not to rest satisfied with a single fact. Let us, therefore, try our question on more general ground. Let us take two portions of the earth, Europe and America for instance, sufficiently extensive to give operation to general causes; let us consider the circumstances peculiar to each, and observe their effect on animal nature. America, running through the torrid as well as temperate zone, has more _heat_ collectively taken, than Europe. But Europe, according to our hypothesis, is the _dryest_.