IMMUNIZATION 



143 



investigated by BOMSTEIN with dogs and guinea-pigs 

 in 1897. He injected, for instance, a dog with 

 a certain quantity of antidiphtheric serum this 

 quantity he termed 7. The next day he took a 

 sample of the blood and subsequently every four 

 days until the content was too small to be measured 

 with certainty. For the measurement BOMSTEIN 

 used the method of EHRLICH ; he mixed different 



xDog 



o Guinea Pig 



13 

 Time in days > 



FIG. 34. 



quantities of blood serum vpith a given quantity of 

 diphtheric poison and investigated how much serum 

 was necessary to render the poison innocuous to 

 guinea-pigs. From this he could calculate the total 

 quantity of antitoxin in the dog's blood, for which 

 he supposed that the total blood-mass was the 

 thirteenth part of the dog's weight. The results 

 found in this manner are contained in the following 

 table and represented in Fig. 34, where log n is 

 plotted against time ; n is the content of antitoxin. 



