SUMMARY 53 



pyogenic action does not manifest itself, because death results 

 too early; but it can be demonstrated, nevertheless, if the same 

 organism be tested in less resistant 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 specific- 

 ally 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 



