But it is unnecessary to multiply evidence in proof of the antiquity of the Negro. His presence in this world was coetaneous with the other families of mankind: here he has toiled with a varied fortune; and here under God--_his_ God--he will, in the process of time, work out all the sublime problems connected with his future as a man and a brother. There are various opinions rife as to the cause of color and texture of hair in the Negro. The generally accepted theory years ago was, that the curse of Cain rested upon this race; while others saw in the dark skin of the Negro the curse of Noah pronounced against Canaan. These two explanations were comforting to that class who claimed that they had a right to buy and sell the Negro; and of whom the Saviour said, "For they bind heavy burdens and grievous to be borne, and lay them on men's shoulders; but they themselves will not move them with one of their fingers."[52] But science has, of later years, attempted a solution of this problem. Peter Barrere, in his treatise on the subject, takes the ground that the bile in the human system has much to do with the color of the skin.[53] This theory, however, has drawn the fire of a number of European scholars, who have combated it with more zeal than skill. It is said that the spinal and brain matter are of a dark, ashy color; and by careful examination it is proven that the blood of Ethiopians is black. These facts would seem to clothe this theory with at least a shadow of plausibility. But the opinion of Aristotle, Strabo, Alexander, and Blumenbach is, that the climate, temperature, and mode of life, have more to do with giving color than any thing else. This is certainly true among animals and plants. There are many instances on record where dogs and wolves, etc., have turned white in winter, and then assumed a different color in the spring. If you start at the north and move south, you will find, at first, that the flowers are very white and delicate; but, as you move toward the tropics, they begin to take on deeper and richer hues until they run into almost endless varieties. Guyot argues on the other side of the question to account for the intellectual diversity of the races of mankind. "While all the types of animals and of plants go on decreasing in perfection, from the equatorial to the polar regions, in proportion to the temperatures, man presents to our view his purest, his most perfect type, at the very centre of the temperate continents,--at the centre of Asia, Europe, in the regions of Iran, of Armenia, and of the Caucasus; and, departing from this geographical centre in the three grand directions of the lands, the types gradually lose the beauty of their forms, in proportion to their distance, even to the extreme points of the southern continents, where we find the most deformed and degenerate races, and the lowest in the scale of humanity."[54]