166 PHYSIOLOGICAL AND PATHOLOGICAL CHEMISTRY. 



4. The acids obtained from the alkaline fluid (F) are to 

 be combined with the volatile acids obtained from the dis- 

 tillation residue (see further below). 



(6) Distillation Residue. 



On account of the larger quantity of the albuminous 

 material used, the quantity of the reagents is also to be cor- 

 respondingly increased (about four times). The more 

 detailed treatment refers especially to the acids obtained 

 from the distillation residue. Some other modifications 

 which facilitate the purification of the individual products- 

 of putrefaction are, however, also advantageous. 



The following scheme is a good one to use: 1 

 Treatment of the Distillation Residue. 



The residue is made alkaline with sodium carbonate, evaporated, and pre- 

 cipitated with alcohol. 



Precipitate (A) (undissolved albu- Alcoholic solution evaporated, 

 min, bacteria, and salts). acidified with sulphuric acid, and 



extracted with ether. 



I 



Ether extract distilled, made alka- Aqueous solution (B) contains 

 line with NaOH, 2 extracted with H,,SO 4 , peptone, and basic sub- 



ether, stances. 



Ether extract (C). Alkaline solution precipitated with 



BaCl 2 and filtered. 



Filtrate treated with HC1 and ether. Precipitate (D) barium soaps. 



Acid aqueous solution (E) basic sub- Ether extract (F^ evaporated and 

 stances. distilled with steam. 



Volatile: fatty acids, homologues Non-volatile: oxyacids, skatol- 

 of benzoic acid; collected in so- carbonic acid, succinic acid, 



dium hydroxide solution, HC1 

 added, and extracted with ether. 



1 The examination for ptomaines is not taken up in the following scheme, 

 In this connection the reader is referred to " Brieger : Investigations on the 

 Ptomaines," Berlin, 1885-1886. 



2 The required quantity of sodium hydroxide solution is measured off. 



