Further Observations on Individual Differences of Human Blood.

In a previous communication we described an agglutinable factor (M), independent of the blood groups and present in many but not in all human bloods. A somewhat higher incidence of M among colored than white individuals, as indicated by our first results, was confirmed by examination on a larger scale; among 902 white individuals 165 (18.3 per cent), and among 338 colored 95 (28.1 per cent) whose blood reacted negatively. A differentiation of bloods (in the same group) lacking or possessing the factor M, was possible also with dried specimens.The heredity of the property M was studied in more than 100 families. The results are in keeping with the assumption that M is inherited as a mendelian dominant. In the following table the families are arranged in 3 classes according to the presence or absence of the factor M in the parents, and its incidence among the offspring is given.It may be mentioned incidentally that the character A present in most bloods of group A, seems to be an inheritable quality. For, in our tests, if the property was not or slightly developed in the blood of both parents, this, as a rule, was also the case for the children.With a method similar to that employed for the detection of M, namely, suitable absorption of certain rabbit immune sera for human blood, two other agglutinable qualities were found which may be denoted as N and P. These reactions, further distinguishing individual human bloods, vary in intensity from very strong to weak or negative.