ISOHEIM AGGLUTININS 169 



on isohemagglutination and have discussed various classifications 

 and theories relative to the inheritance factors involved. Kennedy 

 (1931) published an extensive review of Jansky's work. This is 

 of interest since the original publication is found in few libraries. 

 Classification in Use. — At the present time there are three 

 classifications of the blood groups in use. In the classifications of 

 Jansky and Moss the groups are numbered. While groups I] 

 and III are the same in both classifications, it should be remem- 

 bered that group I of Moss corresponds to group IV of Jansky, 

 and conversely, group IV of Moss is the same as group I of 

 Jansky. 



Classification Based on Agglutinogen Content. — In the third 

 and more recent classification, the groups are identified by the 

 agglutinogen content of the red cells. The cells of the first or 

 "0" group are not agglutinated by the sera of any group and 

 hence may be regarded as not containing an agglutinable sub- 

 stance or agglutinogen. One can imagine that the letter ''0" 

 stands for the German word ohne meaning without. The red 

 cells of the second or A group contain agglutinogen A; of the 

 third, agglutinogen B, while cells of the fourth group contain 

 both A and B agglutinogen and hence the group is called AB. 

 The order of arrangement corresponds to that of the Jansky 

 classification. A comparison of these three classifications with 

 each otlier and with Landsteiner's original groups is summarized 

 in Tal)]o I : 



Table I 



Comparison of Classification of Blood Grottps 



Landsteiner's Three Groups. — In Table I it will be noted that 

 Landsteiner used the letters A, B, and C to designate his three 

 groups. He found that serum of group C agglutinated the red 

 cells of groups A and B; the serum of group A agglutinated the 

 cells of B but not those of C or A; and the serum of group B 

 agglutinated the cells of A but not those of C or its own group 

 B. On the other hand, the serum of the new type, or exception, 



