Reptiles are not exempt from the general law. The saurian (N. 220) tribes of the four quarters of the globe differ in species; and, although warm countries abound in venomous snakes, they are specifically different in different localities, and decrease both in numbers and in the virulence of their poison with decrease of temperature. The dispersion of insects necessarily follows that of the vegetables which supply their food; and in general it is observed that each kind of plant is peopled by its peculiar inhabitants. Each species of bird has its peculiar haunt, notwithstanding the locomotive powers of the winged tribes. The emu is confined to Australia, the condor to the Andes and their declivities, and the bearded vulture or lemmergeyer to the Alps. Some birds, like the common sparrow, have a wide range; but those met with in every country are few in number. Quadrupeds are distributed in the same manner wherever man has not interfered. Such as are indigenous in one country are not the same with their congeners in another; and, with the exception of some kind of bats, no mammiferous animal is indigenous in the Polynesian Archipelago, nor in any of the islands on the borders of the central part of the Pacific. In reviewing the infinite variety of organised beings that people the surface of the globe, nothing is more remarkable than the distinctions which characterise the different tribes of mankind, from the ebony skin of the torrid zone to the fair and ruddy complexion of the Scandinavian—a difference which existed in the earliest recorded times, since the African is represented in the sacred writings to have been as black as he is at the present day, and the most ancient Egyptian paintings confirm that truth; yet it appears, from a comparison of the principal circumstances relating to the animal economy or physical character of the various tribes of mankind, that the different races are identical in species. Many attempts have been made to trace the various tribes back to a common origin, by collating the numerous languages which are or have been spoken. Some classes of these have few or no words in common, yet exhibit a remarkable analogy in the laws of their grammatical construction. The languages spoken by the native American nations afford examples of these; indeed, the refinement in the grammatical construction of the tongues of the American savages leads to the belief that they must originally have been spoken by a much more civilised class of mankind. Some tongues have little or no resemblance in structure, though they correspond extensively in their vocabularies, as the Syrian dialects. In all these cases it may be inferred that the nations speaking the languages in question descended from the same stock; but the probability of a common origin is much greater in the Indo-European nations, whose languages, such as the Sanscrit, Greek, Latin, German, &c., have an affinity both in structure and correspondence of vocables.