INFECTION AND IMMUNITY. 4I5 



Here, again, it appears that the processes of infection 

 and immunity are chemical in their nature, the active 

 poisons of the invading organisms — "the pneumo- 

 toxines " — being instrumental in producing the dis- 

 eased condition, while the antidotal or resisting body of 

 the tissues — " the anti-pneumotoxine " — is the agent by 

 which the poison is neutralized. 



Results in general analogous to those of G. and F. 

 Klemperer have also been obtained by Emmerich and 

 Fowitzky.* 



In the light of these experiments, the hypothesis 

 advanced by Buchner, that the establishment of im- 

 munity is to be explained by reactive changes in the 

 integral cells of the body, receives additional support, 

 and when we consider the observations of Bitter,^ who 

 found that in protective vaccinations against anthrax 

 the vaccines do not disseminate themselves through the 

 body, as is the case when the virulent organisms are 

 introduced, but remain at the point of inoculation, and 

 from this point produce, by the absorption of their 

 chemical products, the systemic changes through which 

 the animal is protected against subsequent infection by 

 the virulent organisms, we feel justified in concluding that 

 the weight of evidence is strongly in favor of this view. 



The experiments that have been cited afford but an 

 imperfect idea of the enormous amount of work that has 

 been done upon these important subjects ; they may, how- 

 ever, serve to indicate the direction in which the lines of 

 research have been laid. As a result of such investiga- 

 tions, our knowledge upon infection and immunity may 

 at present be summarized about as follows : 



1 Emmerich and Fowitzky : Munchener med. Wochenschr., 1891, No. 32. 



2 Bitter: Zeitschritl far Hygiene, 1888, Bd. iv. 



