PTOMAlNS 117 



The poisonous ptomains, which are decidedly in the minority among 

 the entire group, are themselves subject to decomposition, being 

 most abundant in the cultures after a certain period of time, and then 

 decreasing in amount. Very old cultures show almost none of the 

 higher molecular forms of nitrogen, such as ptomains, these substances 

 having been changed into anmionium and nitrate compounds. In 

 sharp contradistinction to the toxins, the yiomalns are by no means 

 specific. No matter upon what medium diphtheria bacilli grow, the 

 toxin produced has qualitatively the same properties, whereas the 

 nature of the ptomains depends not only upon the nature of the bac- 

 teria producing them, but also even more upon the sort of soil upon 

 which the bacteria are grown, the temperature, the duration of the 

 process, and the quantity of oxygen furnished. The same organism 

 may produce totally different ptomains when grown on different 

 media or under different conditions. Another essential difference 

 is that we cannot obtain an immune serum, antagonizing the action 

 of ptomains, by injecting ptomains into animals. 



If ptomains do cause intoxications presumably it is when they are 

 taken in with food in which they have been produced b}- bacterial de- 

 composition. Besides this food poisoning, it is also possible that pto- 

 mains may be formed by putrefaction within the gastrointestinal 

 tract. Another possible source of ptomains is furnished by decom- 

 posing tissues in gangrene. It is doubtful if ptomains are produced 

 in sufF.cient quantities by pathogenic bacteria infecting living tissue 

 to be of any importance. Food poisoning is by no means uncommon, 

 but we do not know how often it is due to ptomains; it may be the 

 result of poisonous materials contained abnormally in the food, that 

 are not ptomains, e. g., botuhsm; or it may be due to an infection of 

 the animal from which the meat came with pathogenic organisms, 

 particularly the B. enteritidis of Gaertner and other bacteria related 

 to the colon-t3'phoid group; or in other ways food ordinarily wholesome 

 may become poisonous.-^ The commonest sources of ptomain poison- 

 ing are supposed to be imperfectly preserved canned meats, sausages, 

 decomposing fish, cheese, ice-cream, and milk.-^^ 



Chemical Composition of Ptomains. — To indicate the composition and nature 

 of ptomains a few of the more important ones will be described. As illustrative 

 of the simpler forms may be mentioned: 



Methvl amine, CHs-NH.. 



Di-methyl amine, CH3 - XH - CH3. 



Tri-methyl amine, CH3 - N - CH3. 



I 

 CH3. 



These bodies, which are commonly found in decomposing proteins are but very 

 slightly toxic, and of little pathological importance. 



23 See Jordan, "Food Poisoning," University of Chicago Press, 1917. 

 -•' All these matters are discussed at length by Vaughan and Xovy, to whose 

 book the reader is referred. 



