PTOMAINES AND PTOMAINE POISONING 401 



amines, others are much more rare and complex; "some are strongly 

 alkaline and basic, others but feebly so; some are liquid, oily and 

 volatile, others fixed and crystalline; some are very prone to change, 

 others quite stable." 



Two thirds of the known ptomaines contain only carbon, hydrogen 

 and nitrogen. These represent the simple ammonia substitution com- 

 pounds. All those that contain oxygen in addition (the so-called 

 oxygenated bases) possess the trimethylamin molecule as their basic 

 constituent. 



Gautier has probably given the best classification of the ptomaines. 

 He divides them into the following groups : 



Monamines of the fatty acid series. 



Diamines of the fatty acid series. 



Guanidines. 



Aromatic ptomaines free from oxygen. 



Oxygenated ptomaines. 



Aromatic oxygenated bases. 



Unfortunately the isolation of a ptomaine from any decomposed or 

 putrid material is a very difficult matter. This is true largely because 

 of the great number, complexity and diversity of the other substances 

 present in the decomposing mass and the fact that these may be at 

 varying stages of putrefaction. 



Some of the ptomaines are volatile and are decomposed at any 

 temperature near that of boiling water. Others, very prone to undergo 

 decomposition, may be destroyed by the action of the reagents used. 

 Hence efforts to determine their presence and character are very apt to 

 be attended with failure. In all of these cases, however, where a suffi- 

 cient amount of a suspected food can be obtained an attempt should 

 be made to determine the presence of any decomposition products that 

 may have been responsible for toxic symptoms. In every case the 

 chemical analysis must be supplemented by a bacteriological examina- 

 tion (much more promising of results) under both aerobic and anaerobic 

 methods to determine the character of the microorganisms present. 

 From pure cultures thus obtained inoculations should be made in suit- 

 able animals to determine their infectious character and filtered cultures 

 used to determine the presence of soluble toxins. 



It is quite probable, as the more recent investigations have shown, 

 that many cases of food poisoning ordinarily classed as of ptomaine 

 origin are in reality due to a direct infection by bacteria in the food 

 which possess pathogenic properties or to toxins formed by them. The 

 tendency to designate all bacterial food poisoning as ptomaine poison- 

 ing is not therefore strictly in accord with the facts as we now know 

 them. 



The resemblance of the ptomaines to the vegetable alkaloids has 

 been noted. These two groups of compounds resemble each other in 



