EXPERIMENT STATION BITLLETINS. 



385 



SERIES IX. 



Acetic acid as met with in the production of vinegar from beer wort was 

 llie second one studied. For tliis 250 c. c. of sterile wort containing 4 

 grams of bone meal were inoculated with a pure yeast. Saccharomyces 

 cerevisiae. and the alcoholic fermentation was allowed to go on for 

 three days at the end of which time a small j)iece of pure mother of 

 vinegar was added to the flask. Acetic fermentation Avas set up at once 

 and after lifteen days chemical determinations were made for the solu- 

 ble phosphoric acid. The amounts found in the inoculated flasks and the 

 uninoculated control are given in Table No. 12. 



Here again we see the marked action of the acid liberating 53.55% 

 of the total phosphoric acid. 



There w^ere probably small amounts of insoluble phosphate in both 

 the milk and the wort which may have been acted upon by the acid 

 present but these have not been taken into consideration and no cor- 

 rection has been made for them in reporting the soluble phosphoric 

 acid as all derived from the bone meal. 



Table No. 12. Solvent Action of Acetic Acid from Beer Wort. 



SERIES X AND XI. 



'F{)v conij>nris(in with the lactic and acetic acid as ]»fodMccd from 

 milk aiul beer wort rcspectix'cly, two more series were pi'e]»ared con 

 taiiiing these acids in cheniically ])ure form but <lilut<Ml with distilled 

 water so tliat the strength ai)|)roaclied that found in the fermentation. 

 This was done for two reasons : 



First, to find out whether the dilute acids would have the same solvent 

 action by themselves as when accompanied by the microorganisms and. 



Second, to see how readily the bone would give up its insoluble ])hos- 

 ]ihato under the a<'tion of the dilute acids. 



So far as these two experiments go, they seem to show that the di 

 lute acids are equally as active and even more so than the acids produced 

 by the microbic fermentations in Series VIII. and IX. It would be per- 

 fectly natural to expect this on account of the possible loose combina- 

 49 



