SUMMARY 53 



action does not manifest itself, because death results too early; but 

 it can be demonstrated, nevertheless, if the same organism be tested 

 in less susceptible animals. While the chicken-cholera bacillus thus 

 kills chickens without evidence of pyogenic action, the injection of 

 sheep, horses, or guinea-pigs leads to the formation of abscesses 

 at the points of injection without a generalized septicemia. This 

 observation in itself goes to show that the specifically toxic effect 

 of the organisms in question is something separate and apart from 

 the pyogenic effect and evidently due to separate substances. 



Aside from their general and non-specific pyogenic properties the 

 bacterial proteins in themselves are not markedly dangerous to the 

 injected animal, but they have gained new importance, since it has 

 been demonstrated that the introduction of foreign albumins, of 

 whatever kind, leads not to increased resistance (immunity) against 

 such proteins, but, on the contrary, to hypersensitiveness (anaphyl- 

 axis, allergia), such that a subsequent injection, after a certain 

 interval of time, may produce the most serious symptoms and even 

 death. As a sensitiveness of this order can very well be imagined to 

 occur in the course of a bacterial disease, the thought has naturally 

 suggested itself that certain symptoms occurring during the later 

 stages of various infections may be explained upon this basis (see 

 section on Anaphylaxis). But even disregarding their possible 

 significance from this point of view, their pyogenic property in 

 itself is sufficient to render them important. Through their attract- 

 ing effect upon the leukocytes (positive chemotaxis) they immediately 

 assume a clinical interest, and in certain infections no doubt (staphy- 

 lococcus, streptococcus, colon bacillus) they are responsible for a 

 large portion of the clinical picture (anemia, hyperleukocytosis, pus 

 formation, fever). 



Summary. To sum up, then, we have seen that the picture of the 

 infectious disease, insofar as the microorganisms themselves are 

 concerned, may be referable (a) to the action of special exotoxins 

 which are actively secreted by the living bacteria; (6) to the action 

 of somewhat less specific endotoxins which enter into play only after 

 the death and destruction of the organisms; and (c) to the relatively 

 non-specific action of the bacterial proteins. The mechanism of the 

 action of these various substances will be considered in some detail 

 in a subsequent chapter. At this place it will suffice to point out 

 that insofar as a direct chemical effect upon the cells of the body 



