270 



Misses M. Stephenson and M. D. Whetham. 



and 0'028 gvm. of lipoid material. Ia an experiment such as the latter, it 

 was hoped that some intermediate products in the change from glucose 

 to fat might be isolated, and experiments with that end in view were 

 made. 



Experiment 2. — Search for Intermediate Products. 



Tive Eoux bottles, in all 750 c.c. of medium, containing the usual inorganic 

 salts, with calcium carbonate and 1 per cent, glucose, were inoculated in the 

 usual way and incubated for fourteen days. The total contents of the five 

 bottles were made up to 2,000 c.c, and filtered. The glucose was estimated 

 in the nitrate and was found to be - ll per cent, (calculated on the original 

 medium). 0'89 per cent, glucose had thus disappeared from the original 

 1 per cent. The medium still had its original reaction, Ph 8. Half the 

 filtrate (corresponding to 375 c.c. of the original medium) was steam-distilled, 

 first from neutral solution. The distillate was collected in cold water in 

 fractions and examined for iodoform-producing bodies ; a slight iodoform 

 reaction was obtained from the distillate collected during the first five minutes, 

 but none from subsequent fractions. The iodoform could only be detected by 

 the smell ; no visible precipitate was obtained. 



The residue in the distilling flask was then acidified with phosphoric acid 

 and again steam-distilled, the distillate being collected in standard 0"1N 

 baryta (50 c.c). At the end of 1\ hours the distillation was stopped and 

 the baryta back-titrated with hydrochloric acid, using phenol phthalein. 

 The difference gave the acidity due to volatile acids and carbonic acid, of 

 which a considerable quantity had come over. The carbonate was then 

 filtered off, washed, transferred to a flask, mixed with 50 c.c O'lN HC1, and 

 boiled under a reflux condenser fitting into the neck of the flask. The residual 

 acid was back-titrated with baryta. The results from 375 c.c. of the original 

 medium were as follows : — 



Carbonate and volatile acids 36 - 2 c.c. 0'HST baryta. 



Carbonate alone 294 „ 01N „ 



Volatile acids 6 8 „ 01N 



Calculated as acetic acid this is' equivalent to 0"011 per cent, acetic acid in 

 the original medium. The residue from the steam-distillation of the total 

 medium (750 c.c) was evaporated on a water-bath to about 150 c.c, filtered, 

 and the filtrate extracted with ether in a continuous extractor for 24 hours. 

 The solid matter was dried and extracted in a Soxhlet apparatus. The 

 ethereal extract from the liquid extraction contained no solid organic acids. 

 The aqueous residue left after the evaporation of the ether was tested for 

 lactic acid by Hopkins' thiophene test ; lactic acid appeared to be present in 



