As I said, the whole thing is preposterous. There is no test which can detect an admixture of Negro blood in the veins of a member of any other race. No human being can tell by text or examination whether a given sample of blood is the blood of a Mongolian, a Caucasian, a Negro, a Malayan or an American (Indian) or that of an individual with a mixture of two or more of these bloods in his veins.