Concerning the distribution of plants and animals, but one general opinion is now sustained with any degree of reason. The beautifully varied systems of vegetation with which the habitable earth is clothed, springing up in rich, spontaneous abundance; the botanical centres of corresponding latitudes producing resemblance in genera without identity of species; their inability to cross high mountains or wide seas, or to pass through inhospitable zones, or in any way to spread far from the original centre,--all show conclusively the impossibility that such a multitude of animal and vegetable tribes, with characters so diverse, could have derived their origin from the same locality, and disappearing entirely from their original birth-place, sprung forth in some remote part of the globe. Linnæus, and many others of his time, held that all telluric tribes, in common with mankind, sprang from a single pair, and descended from the stock which was preserved by Noah. Subsequently this opinion was modified, giving to each species an origin in some certain spot to which it was particularly adapted by nature; and it was supposed that from these primary centres, through secondary causes, there was a general diffusion throughout the surrounding regions. A comparison of the entomology of the old world and the new, shows that the genera and species of insects are for the most part peculiar to the localities in which they are found. Birds and marine animals, although unrestricted in their movements, seldom wander far from specific centres. With regard to wild beasts, and the larger animals, insurmountable difficulties present themselves; so that we may infer that the systems of animal life are indigenous to the great zoölogical provinces where they are found. On the other hand, the harmony which exists between the organism of man and the methods by which nature meets his requirements, tends conclusively to show that the world in its variety was made for man, and that man is made for any portion of the earth in which he may be found. Whencesoever he comes, or howsoever he reaches his dwelling-place, he always finds it prepared for him. On the icy banks of the Arctic Ocean, where mercury freezes and the ground never softens, the Eskimo, wrapped in furs, and burrowing in the earth, revels in grease and train-oil, sustains vitality by eating raw flesh and whale-fat; while the naked inter-tropical man luxuriates in life under a burning sun, where ether boils and reptiles shrivel upon the hot stone over which they attempt to crawl. The watery fruit and shading vegetation would be as useless to the one, as the heating food and animal clothing would be to the other.