METHODS 01'' GAUTIER AND ETARD. 163 



cipitated with an alcoholic solution of mercuric chloride. 

 The mercury precipitate is boiled with water, and on ac- 

 count of differences in solubility of the double compounds 

 with mercury, one ptomaine may be separated from others 

 at this stage of the process. (If thought best, the lead pre- 

 cipitate may be freed from lead and carried through the 

 following steps of the process. Brieger has found small 

 amounts of ptomaines in the lead precipitate only in his 

 work with poisonous mussels.) 



The mercury filtrate is freed from mercury, evaporated, 

 and the excess of hydrochloric acid carefully neutralized 

 with soda (the reaction is kept feebly acid), then it is again 

 taken up with alcohol in order to free it from inorganic 

 salts. The alcohol is evaporated, the residue taken up with 

 water, the remaining traces of hydrochloric acid neutralized 

 with soda; the whole acidified with nitric acid, and 

 treated with phosphomolybdic acid. The phosphomolyb- 

 date double compound is separated by filtration, and de- 

 composed by neutral acetate of lead. This is hastened 

 by heating on the water-bath. The lead is removed by 

 hydrogen sulphide, the filtrate is evaporated to a syrup and 

 taken up with alcohol, from which many ptomaines are 

 deposited as chlorides, or double salts may be formed in 

 the alcoholic solution. Brieger states that the chlorides 

 as deposited from the alcoholic solution are seldom pure, 

 and he advises for their purification, precipitation with 

 gold chloride, platinum chloride, or picric acid, and, on 

 account of differences in solubility of these double salts, 

 the process of purification is rendered more easy. The 

 chloride of the base is obtained by removing the metallic 

 base with hydrogen sulphide ; while the picrate is taken 

 up with water, acidified with hydrochloric acid, and re- 

 peatedly extracted with ether, in order to remove the 

 picric acid. 



The Methods of Gautier and Etard. — The putrid 

 matters, liquid and solid, are distilled at a low temperature 

 in vacuo. The distillate (A) contains a considerable quan- 

 tity of ammonium carbonate, some phenol, skatol, trimethyl- 



