30 INFECTION AND RESISTANCE 



3. Those with three nitrogen atoms such as methyl guanidin 



(c 2 H 7 sr 3 ). 



4. Finally there is an important group which contains oxygen, 

 such as the substance sepsin (C 5 H 14 ]N" 2 O 2 ) obtained by Faust from 

 putrefying yeast cells. 



They are not in all cases protein cleavage products, since bodies 

 of the cholin group, cholin, neurin, and muscarin, the two last named 

 highly toxic, are lecithin derivatives, and Samuely points out that 

 other lipoid cleavage products, always present in decomposing tis- 

 sues, may well contribute to ptomain production in the presence of 

 a source of nitrogen. It is interesting to note also that the vegetable 

 poison muscarin, isolated by Schmiedeberg from mushrooms, is 

 chemically identical with a toxic base found by Brieger in decom- 

 posing fish. 



The ptomains are not poisonous in every case. The chemically 

 simpler ones like methylamin, di- and trimethylamin possess little 

 or no toxicity. Others chemically more complex like cadaverin 

 and putrescin may be capable merely of causing local necrosis, 

 while sepsin, closely related to cadaverin in chemical constitution, 

 but containing oxygen, is a powerful poison which acts violently 

 upon the intestinal blood vessels, causing capillary dilatation, con- 

 gestion, and diapedesis. The presence of oxygen seems indeed to be 

 necessary for the development of strong toxicity (Brieger, Vaughan, 

 and Kovy). Again, the lecithin derivative, cholin, is but weakly 

 toxic, while nciirin is exceedingly poisonous. In putrefying mix- 

 tures these toxic bodies appear on or about the fifth or seventh day 

 after putrefaction sets in, and disappear, by further cleavage, more 

 or less rapidly, yielding less complex nitrogenous substances that are 

 non-toxic. 



With the limited knowledge regarding bacteria and infectious 

 diseases at the disposal of the earlier investigators it was but natural 

 that the discovery of ptomains in cultures of putrefactive bacteria 

 aroused the suspicion that these bodies were responsible for the 

 toxemia of infections disease. 



The search for poisonous substances in pure cultures of patho- 

 genic bacteria was, therefore, assiduously taken r.p by Brieger and 

 his pupils, and, in truth, ptomains were actually found as products 

 of some of the disease-producing micro-organisms, just as they had 

 been found in the mixed cultures involved in the putrefaction of 

 meat. Thus cadaverin was found in cultures of the cholera spiril- 

 lum, another nitrogenous poison, typhotoxin, in those of typhoid 

 bacilli, and still another in tetanus cultures, all of them producing; 

 more or less severe illness when injected .into animals. 



In spite of this evidence, however, we have been forced to con- 

 clude that the ptomains cannot properly be held responsible for bac- 

 9 Meyer and Gottlieb. "Experim. Pharmakologie," 2d ed., p. 262. 



