VI 



ria toxin was observed 1 ), that in repeating the injection 

 of the same dose of toxin on the same animal, smaller 

 and smaller oscillations were obtained. Sometimes we 

 got similar results for the agglutinins, at is seen from 

 curve No. 2, where the second injection of 100 cc. cul- 

 ture produced a much smaller increase of agglutinin 

 than the first injection. On the contrary, curve No. 4 

 indicates the quite different manner of reaction of the 

 rabbits I and III. While the second injection of 2 cc. 

 culture in No. I produced a much smaller oscillation 

 than the first (1 cc.), the case was found entirely I lie 

 reverse in No. III. 



The above demonstrated course of immunisation con- 

 cerns animals, which were previously actively immuni- 

 sed, but exactly the same will be the case for quite 

 fresh animals, never treated before. Owing to the fain! 

 virulence of our B. typhos. culture it is easily done to 

 introduce comparatively large doses of it in fresh rab- 

 bits or goats, and the following agglulinin curve differs 

 in no respects from those observed in actively immu- 

 nised animals. Sometimes a very considerable quantity 

 of agglutinin may be obtained after a single injection. 

 Curve No. 5 indicates such a case, where a goat after 

 an injection of 20 cc. 24h B. typhos. culture showed 

 an increase of agglutinin from to 1666(1 



The proceeding hitherto used, viz. the introduction 

 at once of a great amount of culture into the organism 

 is very unlike what is probably the case under an in- 

 fections disease, for instance typhoid fever. Such cir- 

 cumstances are perhaps a little better reproduced in 

 the following arrangement of the experiment. Instead 



!) Salomonsen et Madsen : Recherches sur la marche de I'iinmiinisation active 

 centre la diphterie. II. 



Annales de 1'Inslitut Pasleur 1899. 



1C 



