The anthropological discussion of the negro problem requires also a word on the “race instinct” of the whites, which plays a most important part in the practical aspect of the problem. Ultimately this phenomenon is a repetition of the old instinct and fear of the connubium of patricians and plebeians, of the European nobility and the common people, or of the castes of India. The emotions and reasonings concerned are the same in every respect. In our case they relate particularly to the necessity of maintaining a distinct social status in order to avoid race-mixture. As in the other cases mentioned, the so-called instinct is not a physiological dislike. This is proved by the existence of our large mulatto population, as well as by the more ready amalgamation of the Latin peoples. It is rather an expression of social conditions that are so deeply ingrained in us that they assume a strong emotional value; and this, I presume, is meant when we call such feelings instinctive. The feeling certainly has nothing to do with the question of the vitality and ability of the mulatto. Still the questions of race-mixture and of the negro’s adaptability to our environment represent a number of important problems. I think we have reason to be ashamed to confess that the scientific study of these questions has never received the support either of our government or of any of our great scientific institutions; and it is hard to understand why we are so indifferent toward a question which is of paramount importance to the welfare of our nation. The anatomy of the American negro is not well known; and, notwithstanding the oft-repeated assertions regarding the hereditary inferiority of the mulatto, we know hardly anything on this subject. If his vitality is lower than that of the full-blooded negro, this may be as much due to social causes as to hereditary causes. Owing to the very large number of mulattoes in our country, it would not be a difficult matter to investigate the biological aspects of this question thoroughly. The importance of researches on this subject cannot be too strongly urged, since the desirability or undesirability of race-mixture should be known. Looking into a distant future, it seems reasonably certain that with the increasing mobility of the negro, the number of full-bloods will rapidly decrease; and since there is no introduction of new negro blood, there cannot be the slightest doubt that the ultimate effect of the contact between the two races must necessarily be a continued increase of the amount of white blood in the negro community.