234 METHODS OF EXTRACTING PTOMAINS. 



fatty acids, as well as the acid and neutral nitrogenous bodies, al- 

 most all of which are crystallizable. The insoluble residue is boiled 

 with dilute hydrochloric acid, with exclusion of air, finally evapor- 

 ated to dryness, and the residue again extracted with alcohol. This 

 nearly alkaline solution (Z)) can be divided by acetate and subace- 

 tate of lead into two portions. 



Gautier has also employed the following method : The putrid 

 liquids, after the removal of fats, are feebly acidified with dilute 

 sulphuric acid, then distilled in vacuo at a low temperature. The 

 distillate contains ammonia, phenol, indol, and skatol. The syrupy 

 residue, separated from any crystals which may have formed, is 

 rendered alkaline with baryta, filtered, and extracted a number of 

 times with chloroform, in order to dissolve the bases. The solution 

 is distilled at a low temperature, either in vacuo or in a current of 

 carbonic acid. The contents of the retort, on being treated with 

 water and tartaric acid, separate into a brown resin and a liquid 

 portion. The latter is removed and treated with a dilute solution 

 of potash, when it gives off the odor of carbylamin, which was dis- 

 covered by Gautier in 1866, and which according to Calmel, is a 

 constituent of the venom of toads. The alkali also sets free the 

 bases, which are removed by extraction with ether, and the ether 

 evaporated in a current of carbonic acid under slight pressure, then 

 under a bell-jar over caustic potash. The bases may be separated 

 by fractional precipitation with platinum chlorid, or, if present in 

 sufficient quantity, by distillation in vacuo. 



In some instances, Gautier modified his method as follows : The 

 alkaline putrid liquid is treated with oxalic acid to free acidulation, 

 and as long as the fatty acids continue to separate. The liquid is 

 then warmed and distilled- until the distillate ceases to be turbid. 

 Pyrrol, skatol, phenol, indol, volatile fatty acids, and some of the 

 ammonia pass over. The portion remaining in the retort is rendered 

 alkaline with lime water and the precipitate which forms and con- 

 tains the greater part of the fixed acids is removed. The liquid 

 portion, which is alkaline, is distilled to dryness, care being taken 

 to receive the distillate in dilute sulphuric acid. The bases and 

 ammonia pass over. The distillate is neutralized with sulphuric acid 

 and evaporated almost to dryness, then decanted from the ammonium 

 sulphate which crystallizes. The mother liquor is extracted with 

 concentrated alcohol, which dissolves the sulphates of the ptomains. 

 After driving off the alcohol the residue is rendered alkaline with 

 caustic soda, and successively extracted with ether, petroleum ether, 

 and chloroform. The lime precipitate is dried and extracted with 

 ether which removes any fixed bases that may be present. 



Remarks Upon the Methods. — Guareschi and Mosso condemn 

 the method of Dragendorff, inasmuch as they have found that basic 



