PTOMAJXS 121 



caused. Moreover, the majority of ptomai'ns are not very poisonous, 

 and highly poisonous ptomains may be produced by non-pathogenic 

 bacteria. As a result, the work on ptomains, which once occupied 

 man}' laboratories and promised to reveal tlie entire chemistry of bac- 

 terial intoxication, has now been almost completely dropped. The 

 interest in ptomains is by no means entirely historical, however, for 

 poisonous ptoinai'iis at times do enter the body and cause illness, 

 sometimes even death. The close chemical resemblance to vegetable 

 alkaloids of some of the ptomains that may arise in decomposing 

 corpses, makes them of great importance to chemists searching for 

 the cause of death in cases of supposed poisoning. Tlierefore the 

 most essential features of the ptomains and their chief known rela- 

 tions to intoxications will be briefly discussed, refeiTing the reader 

 for a full consideration to Vaughan and Novy's "Cellular Toxins" 

 and Barger's "The Simpler Natural Bases." 



The ptomains owe their basic character to nitrogen-containing 

 radicals, principally amino-groups, and hence are formed from ni- 

 trogenous substances, chiefly proteins, which contain their nitrogen 

 in the amino form. Probably most ptomains arise from the decompo- 

 sition of the protein medium upon which the bacteria grow, although 

 undoubtedly part of the ptomains is also formed from the destruc- 

 tion of the bacterial cells themselves; how large a part of the pto- 

 mains is formed by intracellular bacterial processes and how much 

 by cleavage of the proteins of the media by extracellular bacterial 

 enzymes is unknown. The structure of the ptomains shows them to 

 be very closely related to the amino-aeids obtained by cleavage of the 

 protein molecule by enzymes and other hydrolytic agencies ; and the 

 determination of the composition of the several amino-aeids of the 

 proteins has quite cleared up the problem of the origin of the pto- 

 mains. Presumably these secondary changes result from the action 

 of special enzymes upon the amino-aeids. ]\Iost of the ptomains are 

 free from or poor in oxygen, hence reduction processes are probably im- 

 portant in their production. The poisonous ptomains. which are de- 

 cidedly 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 pto- 

 mains, these substances having been changed into ammonium and ni- 

 trate compounds. In sharp contradistinction to the toxins, the pto- 

 mains are hy no means specific. No matter upon what medium diph- 

 theria bacilli grow, the toxin produced has qualitatively the same prop- 

 erties, whereas the nature of the ptomains 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 dura- 

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



