120 Chemical Notices :—M. Pasteur on Fermentation. 
In this case the formula expressing the relation between T 
and h is 
T=883:95—50logh, “. «4 s «> 
and | 
ops OAGR Sry g a a yO 
that is, the velocity of discharge varies directly as the depth of the 
column of liquid. 
XIX. Chemical Notices from Foreign Journals. By Ki. ATKIN- 
son, Ph.D., F.C.S., Teacher of Physical Science in Cheltenham 
College. 
[Continued from vol. xx. p. 523.] 
PASTEUR has for a considerable length of time been 
: e engaged in a research on the nature of alcoholic 
fermentation, a complete account of which he has published in 
the Annales de Chimie et de Physique. Some of the results 
have already appeared in this Journal ; but the importance of the 
subject induces us to lay before our readers the following brief 
summary of the whole investigation, taken from the Répertoire 
de Chimie. : 
According to Pasteur, alcoholic fermentation is the peculiar 
transformation which sugar experiences under the influence of 
beer yeast ; the author shows that glycerine and succinic acid 
are products of the alcoholic fermentation, and treats of their 
estimation and scparation. 
When the fermentation is terminated, the fermented liquid is 
passed through a weighed filter; the increase in weight of the 
filter after being dried at 100°, gives the weight of the yeast 
which has collected at the bottom of the vessel. The filtered 
liquid is then gradually evaporated until it is reduced to a small 
bulk, and the evaporation is terminated in vacuo. This residue 
is exhausted with a mixture of alcohol and rectified ether, which 
dissolves out succinic acid and glycerine. This liquid is evapo- 
rated first on the water-bath, and then, water having been 
added, the evaporation is continued over a gentle flame in 
order to get rid of the ether. The liquid is next exactly 
neutralized by milk of lime, carefully evaporated, and exhausted 
by a mixture of alcohol and ether, which only dissolves the 
glycerine. The residue, which consists of impure succinate of 
lime, is digested with alcohol of 80°; this dissolves the foreign 
matters and leaves the succinate of lime, which is dried and 
- weighed. 
The alcoholic liquid, which contains glycerine, is also evapo- 
rated in the water-bath, and finally 2x vacuo, where it must not 
