PUTREFACTION OF PROTEINS 91 



gens are similarly replaced. All three of these occur in 

 herring brine and are responsible for the characteristic 

 odor of this material. Putrescin and cadaverin— tetrame- 

 thylenediamine and pentamethylenediamine respectively— 

 occur generally in decomposing flesh, hence the names. 

 They are only slightly poisonous. One of the highly poi- 

 sonous ptomaines is neurin C3H13NO or C2H2N(CH3)30H 

 = trimethyl- vinyl ammonium hydroxide. This is a stronger 

 base than ammonia, liberating it from its salts. Numerous 

 other ptomaines have been isolated and described. These 

 bodies were considered for a long time to be the cause of 

 various kinds of "meat poisoning," "ice-cream poison- 

 ing," "cheese poisoning," etc. It is true that they may 

 sometimes cause these conditions, but they are very much 

 rarer than the laity generally believe. Most of the "meat 

 poisonings" in America are due not to ptomaines, but to 

 infections with certain bacilli of the Salmonella group. Occa- 

 sionally a case of poisoning by the true toxin (see Chapter XII) 

 of Clostridium hohdinum occurs, and in recent years has become 

 entirely too common, due to insufficient heating of canned 

 goods. The boiling of such material will destroy this toxin. 

 The safest rule to follow is not to eat any canned material that 

 shows any departure from the normal in flavor, taste or con- 

 sistency. 



As ptomaines result from the putrefaction of proteins, so 

 they are still further decomposed by bacteria, and event- 

 ually the nitrogen is liberated either as free nitrogen or as 

 ammonia. 



Another series of products are the so-called aromatic 

 compounds— phenol (carbolic acid), various cresols, also 

 indol and skatol or methyl indol (these two are largely 

 responsible for the characteristic odor of human feces). 

 All of these nitrogen compounds are attacked by bacteria 

 and the nitrogen is eventually liberated, so far as it is not 

 locked up in the bodies of the bacteria, as free nitrogen or 

 as ammonia. 



The carbon which occurs in proteins accompanies the 

 nitrogen in many of the above products, but also appears in 

 nitrogen-free organic acids, aldehydes and alcohols which 

 are all eventually split up, so that the carbon is changed 



