Formation of inorganic 'Elements during Fermentation. 253 



of a light buff colour remained, weighing, with the crucible, 

 631*97 grs. — 630*4< = \'51 gr. of inorganic matter contained 

 in 500 grs. of sugar and 66'Q grs. of yeast before fermenta- 

 tion. On examination, this ash was found to consist of an 

 alkaline carbonate, traces of a chloride and of a sulphate, phos- 

 phates of lime and magnesia in large proportions, and minute 

 traces of silica and oxide of iron. 



At the expiration of six days, one of the portions which 

 had undergone the vinous fermentation, and which presented 

 the agreeable odour accompanying this stage of fermentation, 

 was evaporated in a mode, and with precautions, exactly 

 similar to the above, and the same phsenomena were ob- 

 served during the operation. The residual liquid evaporated 

 to dryness in the platinum crucible weighing 630'3S grs., and 

 ignited over a gas lamp to full redness as in the first experiment, 

 afforded an ash similar in appearance to the former, which 

 with the crucible weighed 63 1*97 grs. — 630"3S = 1*59 grs. 

 of inorganic matter yielded by 500 grs. of sugar and 66*6 grs. 

 of yeast, after undergoing the vinous fermentation. This ash 

 was similarly constituted with that obtained in the first in- 

 stance. 



From these experiments we find that whilst 500 grs. of 

 sugar and 66*6 grs. of yeast afford previous to fermenta- 

 tion 1*57 grain of inorganic matter ; when fermented they 

 give 1'59 gr., an increase of j^^ gr., or of about l^ per cent.; 

 an increase so trifling that I do not hesitate to refer it to an 

 error of experiment, and not to the formation of inorganic 

 elements during vinous fermentation, which Mr. Rigg asserts 

 is the case. I therefore conclude, contrary to the views enter- 

 tained by Mr. Rigg on this subject, that there is no formation 

 of inorganic matter during the progress of vinous fermenta- 

 tion. 



1 am at a loss to offer any feasible explanation of the enor- 

 mous increase of inorganic matter observed by Mr. Rigg ; 

 the only mode by which this could have taken place, which 

 at present occurs to me, and that an unlikely one, is that suf- 

 ficient precautions were not taken to prevent the introduction 

 of foreign matters by securely covering the solutions of sugar 

 and yeast whilst fermenting ; and that a quantity of dust, the 

 constant plague of a laboratory, became mixed with his solu- 

 tions, and thus led Mr. Rigg to suppose that the alkalies and 

 earths were absolutely formed during fermentation. I may- 

 remark that the paper covers with which my fermenting so- 

 lutions were protected from the dust, were so thickly covered 

 with it, that had the precaution of covering the solutions not 

 been taken, I must have obtained a very considerable increase 



