Articulate language, it is true, acting upon the brain, and in turn being acted upon to the improvement of both, belongs only to man; yet animals are not devoid of expedients for expressing feeling and emotion. It has been observed that no brute ever fashioned a tool for a special purpose; but some animals crack nuts with a stone, and an accidentally splintered flint naturally suggests itself as the first instrument of primeval man. The chief difficulty lies in the high state of moral and intellectual power which may be attained by man; yet this same progressive principle is likewise found in brutes. Nor need we blush for our origin. The nations now most civilized were once barbarians. Our ancestors were savages, who, with tangled hair, and glaring eyes, and blood-besmeared hands, devoured man and beast alike. Surely a respectable gorilla lineage stands no unfavorable comparison. Between the first and the last of these three rallying points, a whole continent of debatable land is spread, stretching from the most conservative orthodoxy to the most scientific liberalism. Numberless arguments may be advanced to sustain any given position; and not unfrequently the same analogies are brought forward to prove propositions directly oppugnant. As has been observed, each school ranks among its followers the ablest men of science of the day. These men do not differ in minor particulars only, meeting in general upon one broad, common platform; on the contrary, they find themselves unable to agree as touching any one thing, except that man is, and that he is surrounded by those climatic influences best suited to his organization. Any one of these theories, if substantiated, is the death-blow of the others. The first denies any diversity of species in creation and all immutability of race; the second denies a unity of species and the possibility of change in race; the third denies all special acts of creation and, like the first, all immutability of race. [Sidenote: PLANTS AND ANIMALS.]