Analysis of the Blood Groups of Children and Infants.

It has long beeii known that, if the blood of one species of animnal is injected into the circulation of another species, the corpuscles of the foreign blood are at once destroyed and their hawlnoglobin set free. An analogous haemolysis may occur when the bloods of certain individuals are mixed with those of other indlividuals of the same species, and the observation of this fact led to the discovery of blood groups among human beings. Landsteiner1 discovered hemolysins an(d iso-hmeniolysins twenty-seven years ago. Six years later Jansky2 divided human blood into four groups, and showed that the blood of each group had a definite relationship to each of the other three groups. In 1910 Moss3 amplified these discoveries and pointed out that the haemolysis is always preceded by agglutination, and that the interaction between the groups might stop at agglutination. There are thus two sets of independent reactions between the serumn of the one group an(d the corpuscles of the other, the seruim of the one aggluitinating or hoemolysing the corpuscles of the other. First Reaction. The corpuscles of Group 1 are agglutinated by the sera of Groups II, III and IV; those of Group II are agglutinated by the sera of Groups III and IV; those of Group III by the sera of Groups II and IV: while those of Group IV are not agglutinated by the serum of any of the other three groups. Second Reaction. The serum of Group I agglutinates no other corpuscles: that of Group II agglutinates the corpuscles of Groups I and 111; that of Grouip III agglutinates the corpuscles of Groups I and II; aind the serum of Group IV agglutinates the corpuscles of Groups I, II and III. These results are set out in Table I.