48 BACTERIAL POISONS 



which becomes apparent at once if we inject suitable animals with 

 killed cultures of the anthrax bacillus on the one hand, and the diph- 

 theria and the tetanus bacillus on the other. It will then be seen 

 that in the anthrax animal, as before, no symptoms develop, while in 

 the others disease and death occur exactly as though they had been 

 infected with the living organisms. As the same effect is obtained, 

 if the injections are made with corresponding cultures that have 

 been passed through porcelain filters, it is evident that the dead 

 bodies of the bacilli, as such, are not concerned in the production of 

 the result. This is manifestly due to the presence of poisons in the 

 tetanus and diphtheria filtrates and their absence in the anthrax 

 cultures. The existence of a clinical picture of tetanus or diphtheria 

 infection, in other words, the development of the corresponding 

 infectious disease, is thus explained, as are also the negative results 

 in anthrax. 



/ The question now arises: Are all the so-called infectious diseases 



r j due to toxic substances derived from the offending parasites? This 

 v v j-^^ question can, I think, be answered in the affirmative for those dis- 

 eases of which the infecting agent is known. Regarding the nature 

 of the toxic agents, however, which are responsible for the symptom- 

 complex of the various infectious diseases, and the mechanism of 

 their action, our knowledge is as yet very meager. 



Ptomains. In the earlier days of bacteriology, when Brieger 

 especially had shown in a long series of elaborate investigations 

 that definite nitrogenous compounds of basic nature and alkaloid- 

 like properties the so-called ptomains were formed from animal 

 matter in consequence of bacterial decomposition, and that some of 

 these bodies were poisonous, hope ran high that the application of 

 the same methods to cultures of the pathogenic bacteria proper would 

 lead to the discovery of definite compounds, to which the symptoms 

 of the corresponding diseases could be attributed. These hopes 

 were, however, soon shattered. For a short time, it is true, the 

 discovery of ptomains, supposedly specific of various diseases, was 

 announced from different laboratories. Brieger himself isolated a 

 "typhotoxin" and a "tetanin," and I well remember, when working 

 in Gautier's laboratory, translating into French the announcement 

 from a British source of specific ptomains for scarlatina, measles, 

 mumps, etc. Later research then showed that while some ptomains 

 are unquestionably poisonous and may occasionally play a role as 



