PTOMAINES 273 



The importance of the presence of these bodies in de- 

 composing animal matter cannot be over-estimated. In 

 various [plants there occur a whole series of bodies, of 

 which strychnine, quinine, atropine, nicotine, morphine, 

 and others are well-known examples. All of these exert a 

 Bpecific action on the animal body, many of them causing 

 very toxic effects. 



A number of the ptomaines have been built up arti- 

 ficially, without the aid of micro-organisms, by purely 

 chemical synthetical methods. Trimethylamine, dimethy- 

 lamine, and pentamethyline diamine (cadaverinj) may be 

 obtained from the products of the putrefaction of the 

 animal body, and also may be prepared by the chemist 

 artificially, the synthetically-prepared product giving rise, 

 on inoculation into the animal body, to all the symptoms 

 and post-mortem appearances of an attack of cholera. 

 The ptomaines are nitrogenous bases having an alkaline 

 reaction, and combining with acids to form salts. Their 

 chemical constitution is very complex, and, like many of 

 the vegetable alkaloids, they are derived from the base 

 pyridine. The following are some of the characters of 

 the vegetable alkaloids, which are the active principles of 

 plants, and to which the ptomaines are strictly allied. 

 They are very poisonous, having a bitter, acrid, and 

 pungent taste. The alkaloids combine with acids to form 

 salts, and are precipitated from their saline solutions by 

 the addition of alkalies. They are mostly crystallised and 

 colourless, insoluble in water, but soluble in alcohol, chloro- 

 form, benzine, and some in ether. The salts, on the other 

 hand, are soluble in water, less so in alcohol, insoluble in 

 chloroform, etc. Alkaloids are mostly precipitated by one 

 or more of the following reagents : Potassio-mercuric 

 iodide, gold chloride, tannic acid, phospho-molybdic acid, 

 and picric acid. Alkaloids are either amides or amines. 



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