BACTERIOLYSINS AND H&MOLYSINS 107 



biological constitution than those of species C, 

 etc. 



Moss finds that isolysins occur in about 2 5 % of adult 

 human individuals, and that the relative frequency is 

 the same in health and disease, so that the presence 

 of isolysins has no diagnostic significance. The sub- 

 ject has recently acquired importance because of the 

 revival of homologous transfusion, and it is customary 

 now to always test the blood of both donor and re- 

 cipient prior to carrying out such a transfusion. 

 The technique of this test is given on page * and 

 is carried out in the same manner and at the same 

 time as the test for iso-agglutinins. 



The fact that after injections of large amounts of 

 cells of the same species isolysins develop, but that 

 autolysins are almost never formed, caused Ehr- 

 lich and Morgenroth to assume that the body pos- 

 sesses distinct regulating functions which naturally 

 prevent the formation of the highly destructive 

 autolytic substance. It is obvious that if there 

 were no such regulating facilities, the absorption of 

 large bloody effusions and hemorrhages might lead 

 to the formation by the organism of autolysins 

 against its own blood cells. Gengou, a pupil of 

 Metchnikoff, believes he has shown experimen- 

 tally that the destructive action of these auto- 

 lysins is hindered by the simultaneous production 

 of an auto-antiimmune body which immediately 

 inhibits their action. 



