PTOMAINS 117 



almost none of the higher molecular forms of nitrogen, such as 

 ptomains, these substances having been changed into ammonium 

 and nitrate compounds. In sharp contradistinction to the toxins, 

 the ptomains are by no means specific. No matter upon what 

 medium diphtheria bacilli grow, the toxin produced has qualita- 

 tively the same properties, whereas the nature of the ptomai'ns 

 depends not only upon the nature of the bacteria 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 pro- 

 duce 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. 



Ptomains are chiefly the cause of disease when they are taken 

 in with food in which they have been produced by bacterial 

 decomposition. Besides this food poisoning, it is also possible 

 that ptomains may be formed by putrefaction within the gastro- 

 intestinal tract. Another possible source of ptomains is fur- 

 nished by decomposing tissues in gangrene. It is doubtful if 

 ptomains are produced in sufficient quantities by pathogenic 

 bacteria infecting living tissue to be of any importance. Food- 

 poisoning is by no means uncommon, but it is not always due 

 to ptomains ; it may be the result of poisonous materials con- 

 tained abnormally in the food, that are not ptomains, e. g., ergot- 

 ism ; 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- 

 typhoid group ; or in other ways food ordinarily wholesome may 

 become poisonous. The commonest sources of ptomam poison- 

 ing are imperfectly preserved canned meats, sausages, decom- 

 posing fish, cheese, ice-cream, and milk. l 



Chemical Composition of Ptomains. To indicate the 

 composition and nature of ptomains a few of the more impor- 

 tant ones may be described. As illustrative of the simpler 

 forms may be mentioned : 



Methyl amine, CH 3 NH 2 . 



Di-methyl amine, CH 3 NH CH 3 . 



Tri-methyl amine, CH S N CH 3 . 



CH 3 



These bodies, which are commonly found in decomposing 



1 All these matters are discussed at length by Vaughan and Novy, to whose 

 book the reader is referred. 



