490 THE BIOLOGICAL BASIS OF INDIVIDUALITY 



Forssman differential, which likewise occurs in sheep corpuscles. But the 

 antigen common to sheep and cattle corpuscles which gives rise to this 

 hemolytic amboceptor is not possessed by all cattle, but only by some indi- 

 viduals. Thus the presence of groups can be demonstrated also in the case of 

 cattle corpuscles. Cattle contain B x and B 2 receptors. B x is the differential of 

 those blood corpuscles which are not hemolyzed by anti-sheep-rabbit serum, 

 while B 2 cattle corpuscles are hemolyzed by anti-sheep-rabbit serum. 



In general, in lower animals the agglutinogen B apparently is more fre- 

 quent than A. Thus in the dog, in the rabbit, and, as mentioned above, also 

 in New World monkeys, B is .present, and correspondingly the agglutinin 

 alpha is found in the serum of such individuals ; also in the guinea pig a very 

 weak B has been noted. More recently the occurrence of B differentials in 

 erythrocytes and of anti-B in sera has been further analyzed by Friedenreich 

 and With. It was found that among the B differentials, different subgroups can 

 be distinguished, namely B x , B 2 and B 3 . The separation of these fractions was 

 accomplished by means of absorptions of normal human and animal sera by 

 human B corpuscles, as well as by B corpuscles from various animal species. 

 Rabbit corpuscles were observed to contain B 2 and B 3 differentials, but not 

 B lf which is peculiar to man. The guinea pig erythrocyte has a weak B dif- 

 ferential ; also, dog, rat and hog have B components. The same facts apply to 

 cattle, sheep and goats, although their erythrocytes are not agglutinated by 

 anti-B serum. In conformity with the lack of B x in the erythrocytes of these 

 various species, the sera of the latter possess anti-B x substance ; only the 

 chicken serum shows anti-B substance, and correspondingly, the chicken 

 erythrocytes are free of the B differential. That different kinds of B differen- 

 tial may be distinguished explains also the occurrence, in some species, of B 

 in the red blood corpuscles and of agglutinin beta in the serum of the same 

 individual ; in such cases, B and beta represent different fractions, as for in- 

 stance, B 2 in the corpuscles and anti-B x in the serum. In this way auto- 

 agglutination would be avoided. 



In Polish chickens the sera of many individuals strongly agglutinate hu- 

 man erythrocytes O and B, but not A. Conversely, according to Karshner, 

 human serum belonging to blood-group B-alpha gives the greatest number of 

 positive agglutinations with chicken erythrocytes, while human sera of blood- 

 group A, containing anti-B agglutinin, give the least. Dunn and Landsteiner, 

 by means of anti-chicken-rabbit sera found in several chicken families an 

 agglutinogen, the hereditary transmission of which was apparently deter- 

 mined by a single dominant gene. Karshner, by means of isoagglutination 

 reactions, distinguished three blood groups in chickens, the largest group 

 consisting of individuals in which neither agglutinogens nor agglutinins 

 could be demonstrated. On the other hand, Shimidzu did not find that the 

 weak isoagglutinations which occur in chickens permit the differentiation of 

 different groups. However, if the agglutination of the erythrocytes of in- 

 dividual chickens is tested with rabbit-anti-chicken immune sera' or with 

 various heterogenous sera, individual differences in the majority of all in- 

 dividuals examined could be found. Such experiments were carried out by 



