THE PTOMAINES AND SOLUBLE FERMENTS 309 



separated by filtration. This filtrate is evaporated 

 to a thin syrup, and this is extracted with amylic 

 alcohol The amylic solution is treated with water, 

 concentrated by evaporation, then acidulated with 

 sulphuric acid, and washed several times with ether, 

 which frees it from the oxy-aromatic acids. The 

 aqueous-acid liquor is then concentrated to a 

 quarter of its volume. After standing twenty-four 

 hours, the precipitate which forms is dissolved in 

 boiling water and decomposed by sulphuretted 

 hydrogen. In concentrating the liquors, Brieger 

 crystallises at once various mineral or organic salts 

 which are rejected, then the dried residue is treated 

 with absolute alcohol, which, after concentration, 

 deposits the putrefactive bases or ptomaines in the 

 crystalline condition. The various ptomaines are 

 now separated by the difference of their solubility, 

 or by fractional precipitation with platinic chloride, 

 auric chloride, picric acid, etc. 1 (3) Luff's method 

 is used for the extraction of ptomaines contained 

 in abnormal urines. A considerable quantity of 

 the urine is made alkaline by a solution of sodium 

 carbonate, and then agitated with half its volume 

 of ether. The ethereal solution (after standing) is 

 filtered and agitated with a solution of tartaric acid. 

 The tartaric acid combines with any ptomaines pre- 

 sent, forming soluble tartrates, and the solution of 

 tartrates forms the lower layer of the liquid mass. 

 The tartaric acid solution (after being separated 

 from the ether) is also made alkaline by the 



J See Brieger's Ueber Ptomaine 1885; Welter e Untersuchun- 

 gen ilber Ptomaine, 1885 ; Untersuchungen uber Ptomaine, 1886. 



