148 



IMMUNIZATION 



This absorption, for instance, plays a very im- 

 portant role in the diversion of complement (cf. 

 p. 138). If we inject antidiphtheric horse-serum into 

 a nearly related animal such as an ass, we might 

 expect the antitoxin to disappear more slowly than 

 if injected into a dog or a guinea-pig. This experi- 

 ment has been carried through by BULLOCH (in 1898). 

 As the following table and the diagram, Fig. 35, 

 indicate, the antitoxin required 37-5 days to sink 

 to the half value, i.e. about twelve times longer than 

 in BOMSTEIN'S experiments. In this case the injec- 

 tion was subcutaneous, as is seen from the first two 

 values in the table. If the total quantity of anti- 

 toxin had spread uniformly in the blood an initial 

 value 19 per cc. ought to have been observed. 

 The value 16 after one day reaches nearly this 

 theoretical value 19. 



PASSIVE IMMUNIZATION OF AN Ass WITH ANTIDIPHTHERIC 

 SERUM FROM HORSE (BULLOCH) 



