Group specific flocculation reactions with alcoholic extracts of human blood.

In a previous communication it was stated that by adding inactivated hemolytic immune sera to emulsions of alcoholic extracts of blood, flocculation reactions can be obtained. 1

In continuation of our experiments, tests were made with rabbit anti-human blood immune sera. It was found that in this case also a certain number of the immune sera gave positive reactions under the conditions of our experiments. The immune sera were prepared by injections of Group I and of Group II blood corpuscles (American nomenclature). 2 Some of the most active anti-group II immune sera showed a distinctly stronger flocculation with the extracts of II corpuscles than with those of Groups I and III (as shown in the table). To make the emulsions, 1 cc. of the filtered alcoholic extract prepared as described previously 1 was blown with a pipette into 5 cc. of saline solution.