228 LECTURES ON IMMUNITY 



constant. This is actually found to be the case ; for in- 

 stance, the degree of haemolysis 64 corresponds to the fol- 

 lowing values of -: = 0.033, = 0.04, and-^- = 0.04. 



a 300 150 100 



This is evidently true only if the haemolytic action is of 

 such a magnitude as it is possible to reach with the quan- 

 tity of b present ; and this circumstance indicates that the 

 said rule is only a rather rough approximation. The rule 

 stated leads to the consequence that the maximum appears 

 at a lower value of a for a lower value of b, and the values 

 of a at the maximum are nearly proportional to the value 

 of b (80 : 10 = 8 ; 50 : 6 = 8.3 ; 30 : 4 = 7.5). 



It had been observed in different investigations that 

 the quantity of alexin necessary to produce complete 

 haemolysis is the less the greater the quantity of immune- 

 body that had been used for the " sensibilisation " of the 

 erythrocytes. 1 This matter was subjected to a closer 

 investigation by Morgenroth and Sachs. 2 They found 

 that in one case (viz. haemolysis of sheep erythrocytes by 

 means of immune-bodies from goat blood and alexin 

 from guinea-pig serum) the quantity (b) of alexin was 

 often nearly inversely proportional to the quantity (a) of 

 immune-body used. In another case (haemolysis of ery- 

 throcytes from ox blood with immune-body from goat- 

 serum and an alexin from serum of guinea-pig or of rabbit 

 or even of sheep) the quantity of alexin necessary for com- 

 plete haemolysis was independent (or nearly so) of the 

 quantity of immune-body used. In other cases the same 



J v. Dungern: Munch, med. Wochenschrift, No. 20 (1900); Gruber: 

 Wiener klin. Wochenschrift^Q. 15 (1902). 



2 Morgenroth and Sachs: Berl. klin. Wochenschrift, No. 35 (1902). 



