Entertaining these views upon the fundamental questions concerning the races, the next point for consideration is the policy to be adopted under present circumstances, in order to increase the amount of good which is within our grasp and lessen the evil which we may avert. This will be for another letter. Very truly yours, LOUIS AGASSIZ. FROM THE SAME TO THE SAME. August 10, 1863. MY DEAR DOCTOR, I am so deeply impressed with the dangers awaiting the progress of civilization, should the ideas now generally prevalent about amalgamation gain sufficient ascendancy to exert a practical influence upon the management of the affairs of the nation, that I beg leave to urge a few more considerations upon that point. In the first place let me insist upon the fact that the population arising from the amalgamation of two races is always degenerate, that it loses the excellences of both primitive stocks to retain the vices or defects of both, and never to enjoy the physical vigor of either. In order clearly to appreciate the tendencies of amalgamation, it is indispensable to discriminate correctly between the differences distinguishing one race from another and those existing between different nationalities of the same race. For while the mixture of nationalities of the same race has always proved beneficial as far as we are taught by history, the mixture of races has produced a very different result. We need only look at the inhabitants of Central America, where the white, the negro, and the Indian races are more or less blended, to see the baneful effects of such an amalgamation. The condition of the Indians on the borders of civilization in the United States and in Canada, in their contact with the Anglo-Saxons as well as with the French, testifies equally to the pernicious influence of amalgamation of races. The experience of the Old World points in the same direction at the Cape of Good Hope, in Australia; everywhere, in fact, history speaks as loudly in favor of the mixture of clearly related nations as she does in condemnation of the amalgamation of remote races. We need only think of the origin of the English nation, of that of the United States, etc. The question of breeding in-and-in, that of marriage among close relations, is again quite distinct. In fact, there is hardly a more complicated subject in physiology, or one requiring nicer discriminations, than that of the multiplication of man, and yet it is constantly acted upon as if it needed no special knowledge. I beseech you, therefore, while you are in a position to exert a leading influence in the councils of the nation upon this most important subject to allow no preconceived view, no favorite schemes, no immediate object, to bias your judgment and mislead you. I do not pretend to be in possession of absolute truth. I only urge upon you the consideration of unquestionable facts before you form a final opinion and decide upon a fixed policy. Conceive for a moment the