=Inter-Racial Marriage.--=Some of the dangers of racial deterioration which threaten us because of our laxity regarding immigration have already been indicated. It is high time that we give this whole question the most serious consideration of which we are capable. From the rate at which immigrants are increasing it is obvious that our very life-blood is at stake. For our own protection we must face the question of what types or races should be ruled out. Aside from the dangers which lie in the defective or unsuccessful types already discussed in Chapter IX, many students of heredity feel that there is great hazard in the mongrelizing of distinctly unrelated races no matter how superior the original strains may be. Unfortunately there is a great lack of reliable data on this point. The mulatto of our own country, the Eurasians in India and the mixed races of South America are, according to the testimony of many observers, eloquent arguments against such hybridization. Agassiz remarked on this point as follows: "Let any one who doubts the evil of the mixture of races and who is inclined from mistaken philanthropy to break down all barriers between them come to Brazil. He can not deny the deterioration consequent upon the amalgamation of races, more wide-spread here than in any other country in the world, and which is rapidly effacing the best qualities of the white man, the Indian, and the negro, leaving a mongrel nondescript type deficient in physical and mental energy." Of the American mulatto one not infrequently meets with the assertion that he is on the average inferior mentally, morally and physically to either the white or the negro race. Thus Doctor J. B. Taylor[17] states that, "It is demonstrated by well-attested facts that these hybrids of black and white are vastly more susceptible to certain infections; their moral as well as physical stamina is lower than that of either original race." Others would deny that conclusive evidence to this effect exists. However, it is certain that under existing social conditions in our own country only the most worthless and vicious of the white race will tend in any considerable numbers to mate with the negro and the result can not but mean deterioration on the whole for either race.