350 



Dr. P. F. Frankland and Mr. J. J. Fox. [June 20, 



severally treated witli an excess of pure barium carbonate, boiled for 

 one hour to expel carbonic anhydride, and then filtered ; the filtrate 

 containing the barium salt of the volatile acid was then evaporated 

 and weighed after drying until constant at 130° C. A barium 

 determination was then made by conversion into sulphate, and from 

 the proportion of barium sulphate obtained the composition of the 

 volatile acid was calculated. The following results were obtained 

 when the several distillates were treated as above : — 



I. 6*636 grams Ba-salt dried at 130° C. gave 91*23 per cent. 

 BaS0 4 . 



II. 4-158 grams Ba-salt gave 91*29 per cent. BaS0 4 . 



III. 2*561 grams Ba-salt gave 91*40 per cent. BaS0 4 . 



IV. 1*217 grams Ba-salt gave 91*83 per cent. BaS0 4 . 

 V. 0*321 gram Ba-salt. Barium-determination lost. 



With the exception of that in fraction IY, all the barium deter- 

 minations show that the only volatile acid present was acetic acid, 

 inasmuch as the theoretical quantity of barium sulphate obtainable 

 from barium acetate is 91*37 per cent. 



Thus even the proportion of barium sulphate obtained in frac- 

 tion IY differs but slightly from the theoretical amount for barium 

 acetate, and the discrepancy was probably due to the presence of a 

 little barium carbonate (indicated by slight effervescence on treating 

 the residue with hydrochloric acid, and due to the permanent solu- 

 bility of the barium carbonate even on boiling), for no formic acid 

 could be discovered by the silver nitrate reaction. 



The total amount of Ba-salt obtained, viz., 14*893 grams, may be 

 calculated as pure acetic acid, of which there were, therefore, 

 7*008 grams produced in this fermentation. 



Separation of Fixed Acids, 8fc. — After distilling off the volatile acid 

 as above, the calcium in solution was precipitated with sodium car- 

 bonate, and the solution after filtering was evaporated to dryness. 

 The residue thus obtained was placed in a Soxhlet's apparatus, and 

 extracted with absolute alcohol, which would dissolve any sodium 

 lactate, but leave any sodium succinate, and the greater part of the 

 sodium chloride undissolved. Both the residue and the alcoholic 

 extract, after evaporating the alcohol, were dissolved in water, acidu- 

 lated with hydrochloric acid, and then repeatedly shaken with ether. 

 The ethereal extract of the solution of the residue yielded on evapo- 

 ration 0*0215 gram of substance, which on ignition gave the suffoca- 

 ting fumes characteristic of succinic acid. 



No lactic acid was found in the ethereal extract of the other 

 portion. 



Both the residue and the alcoholic extract referred to above might 

 contain unaltered mannitol, which would have to be separated from 



