462 BAOTERIOLOOY. 



actually dead from exposure to these substances correc- 

 tion of the abnormal reaction was followed by further 

 development of the organisms. Sirotiain also states 

 that materials containing the products of growths of 

 bacteria, so long as they are maintained at a neutral or 

 only slightly alkaliue reaction, serve very well as media 

 upon which to cultivate again the same organism that 

 produced them, providing the nutritive elements have 

 not been entirely exhausted. He remarks that, if in such 

 a concentrated form as we find the life-products of bac- 

 teria in the medium in which they are growing, no 

 inhibitory compounds beyond acids and alkalies are to 

 be detected, it is hardly probable that they are produced 

 in the tissues of the living animal, and retained there, 

 to a degree sufficient to prevent the growth of bacteria 

 that may subsequently gain entrance to these tissues, 

 after the disappearance of the organisms concerned in 

 the primary invasion. On the other hand, Salmon and 

 Smith,^ E.OUX and Chamberland,^ aud others had 

 demonstrated that a sort of immunity against certain 

 forms of infection may be afforded to susceptible ani- 

 mals by the injection into their tissues of the products 

 of growth of particular organisms which, if themselves 

 introduced into the animal body, would produce fatal 

 results. In the light of subsequent experiments, how- 

 ever, the interpretation of this phenomenon is probably 

 not that claimed by the supporters of this hypothesis. 



As opposed to the view of Chauveau, Pasteur^ and 

 certain of his pupils believed that the immunity fre- 

 quently afforded to the tissues by an attack of infection. 



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



2 Annates de I'lnstitut Pasteur, 1888-89, tomes 1., ii. 



3 Bull, de I'Acad. de M6d., 1880. 



