INFECTION AND IMMUNITY. , 423 



pearance of the organisms concerned in the primary 

 invasion. On the other hand, Salmon and Smith, 1 

 Roux and Chamberland, 2 and others had demonstrated 

 that a sort of immunity against certain forms of infec- 

 tion may be afforded to susceptible animals by the injec- 

 tion into their tissues of the products of growth of par- 

 ticular organisms which, if themselves introduced into 

 the animal body, would produce fatal results. In the 

 light of subsequent experiments, however, the interpre- 

 tation of this phenomenon is not that claimed by the 

 supporters of this hypothesis. 



As opposed to the view of Chauveau, Pasteur 3 and 

 certain of his pupils believed that the immunity fre- 

 quently afforded to the tissues by an attack of infection, 

 or following upon vaccination against infection, was due 

 rather to an abstraction from the tissues, by the organ- 

 isms that were concerned in the primary attack, of a 

 something that is necessary to the growth of the infect- 

 ing organism shotrld it gain entrance to the body at any 

 subsequent time. This view is known as the exhaustion 

 hypothesis. 



As to the exhaustion hypothesis of Pasteur, there is, 

 as yet, no evidence whatever for its support. The work 

 of Bitter, 4 which was undertaken with the view of de- 

 termining if, in the process of acquiring immunity, there 

 occurred this exhaustion from the tissues of material 

 necessary to the growth of bacteria that might gain en- 

 trance to them at some later date, gave only negative 

 results. The flesh of animals in which immunity had 

 been produced contained all the elements necessary for 



1 Proc. of the Biol. Soc., Washington, D. C., 1886, vol. iii. 



2 Annales de Tlnstitut Pasteur, 1888-89, tomes i., ii. 



3 Bull, de 1'Acad. de Med., 1880. 4 Zeitschr. fur Hygiene, 1888, Bd. iv. 



