Note on Individual Differences in Human Blood.

1. Previously an agglutinable property of human blood designated as P was described, which could be demonstrated by the use of immune agglutinins from rabbits, 1 and it was mentioned 2 that reactions of a more or less similar specificity occur with a certain type of irregular human isoagglutinins. Inasmuch as these 2 reagents are not always easily available it seems worth mentioning that similar results can readily be obtained with various absorbed normal animal sera, e. g., those of horses, pigs and rabbits. In horse serum the agglutinins were found rather frequently.

2. An anti-dysentery immune serum from a goat was shown by Eisler 3 to contain agglutinins for human blood which can be absorbed by dysentery bacilli (Shiga). Using this serum, kindly supplied to us by Eisler, we were able to confirm fully these interesting observations. Furthermore we found that after absorbing the serum with cells of the sub-group A 1 the supernatant fluid agglutinated most cells of sub-group A 2 , O, and probably B, distinctly more strongly than those of sub-group A 1 , in a similar way as certain exceptional human sera. 4 Whether this is a singular occurrence or can be reproduced with other dysentery sera is being investigated.