608 



THE GUM FERMENTATION OF SUGAR CANE JUICE, 



the separated fatty acid was 30-8° which is sufficiently near the 

 melting point of capric acid (31-3°) to identify it with this acid. 

 The organic acids were extracted from the acid fluids by per- 

 colation with ether. The extraction was generally continued for 

 12 hours; sometimes with a large quantity of fluid the time 

 occupied was 24 hours. After the extraction the ether was dis- 

 tilled off and the acids separated by a combination of the methods 

 recommended by Schneider* and Harden, f 



Analysis of the Ethereal Residue. 



Ethereal residue diluted with water and distilled in a current of steam until 

 the distillate had a constant acidity. 



Residual liquor divided into portions. 



Portion digested with ZnO, filtered 

 while hot and the zinc lactate 

 proved by its solubility and also 

 microscopically. 



Portion digested with CaCO 3 on water 

 bath for several hours, filtered. 



Piesidue dis- 

 solved in 

 acetic acid 

 and tested 

 for oxalic 

 acid: none 

 found. 



Filtrate evaporated to 

 dryness, extracted with 

 90 % alcohol. 



No residue 



of 



succinate 



Extract 



contained 



lactate. 



Portion of solution of calcium salt 

 crystallised, dried and the calcium 

 estimated. 



Distillate evaporated with excess of 

 CaCOg, treated with absolute alcohol, 

 filtered. 



Residue extracted 

 with water and so- 

 lution tested for 

 acetic and formic 

 acids. 



Acetic and formic 

 acids found. 



Filtrate. 



Portion tested 

 withZn(N03)2for 

 valeric acid; none 

 found. 



Remainder eva- 

 porated and resi- 

 due tested for 

 butyric acid. 

 Butyric acid found 



Lactic acid was proved by the microscopical appearance of its 

 barium, calcium and zinc salts, by its comparatively non-volatile 



* Schneider, Journ. Chem. Soc. 1900, Abs. ii., 177. 

 t Harden, ibid. 1901, 614-5. 



