VI 



This experiment is still more striking than the precedent, 

 as the injections were continued 18 days after the maxi- 

 mum was reached. It is of interest to notice the almost 

 critical fall in the 24 hours after the acme, during which 

 the agglutinating power of the serum decreased from 

 250 to 90. The interpretation of this phenomenon will 

 later on be given. 



The last mentioned curve resembles the similar ex- 

 periments with diphtheria toxin in horses, which were 

 undertaken by Salomonsen and Madsen 1 ). This was 

 the case, although these injections, due to practical pur- 

 poses, were only continued for about 8 days. 



PASSIVE IMMUNISATION. 



The chief object for our experiments was to examine 

 the fate of the agglutinins, introduced into the circula- 

 tion. The serum of the animals was previously tested 

 for normal agglutinating power; then the injection of 

 the agglutinin was made, in the case of goats into the 

 jugular vein, in the case of rabbits into the ear vein; 

 the animals were allowed to run around for a few 

 minutes and the first sample of blood after the injec- 

 tion was drawn from the other jugular vein, resp. ear 

 vein. 



As examples of the experiments the following may 

 be quoted: 



A fresh goat got on the 18 / 4 an injection into the 

 jugular vein of 200 cc. cholera-agglulinin from goat. 

 The agglutinating power of the serum, which was 

 before the injection, was immediately thereafter 11,1. 

 As curve No. 6a indicates, the agglutinin fell in the first 



Recherches sur la marche dc I'immunisation active centre la diphtcrie. II. 

 Ann. de 1'Inst. Pasteur IN!)!). 



18 



