INFECTION AND IMMVNITY. 563 



the formation of the protecting substance. They like- 

 wise isolated from the serum of immunized animals 

 a proteid that possessed the same powers as the serum 

 itself, viz., of affording immunity and curing the 

 disease. 



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- 

 toxins " — being instrumental in producing the diseased 

 condition, while the antidotal or resisting body of the 

 tissues — "the anti-pneumotoxin " — 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 site 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. 



'Emmerich and FoTidtzky: Muiichener med. Wochensohrift, 1891, 

 No. 32. 

 2 Bitter: Zeitschrift fur Hygiene, 1887, Bd. iv. 



