Formation of inorganic Elements during Fermentation, 253 
of a light buff colour remained, weighing, with the crucible, 
631*97 «TS. — 630*4? = 1*57 gr. of inorganic matter contained 
in 500 grs. of sugar and 66*6 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 phsenoraena were ob- 
served during the operation. The residual liquid evaporated 
to dryness in the platinum crucible weighing 630*38 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 631*97 grs. —630*38 = 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 Jq gr., or of about li 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. 
I 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 
