42 
PROCEEDINGS OF THE 
Mr. G. E. Dennes read a Translation of Professor Meyen’s 
Memoir, on the Circulation of the proper juice in plants. 
MAY 18th. 
J. E. Gray, Esq., F.R.S., President, in the Chair. 
A Paper was read by Mr. Manley Hopkins on the subject 
of Vegetable Fermentation, of which the following is but 
a brief abstract.* 
“ The author, after remarking on the changes and muta- 
tions which are continually undergoing in bodies — in the 
vegetable and mineral kingdoms in particular — proceeded, 
first, to describe the phenomena attendant on the formation 
of sugar, and the various modes in which sugar is formed. 
Mr. Hopkins conceives, that all the products of fermenta- 
tion arise from the diminution of carbon ; and that the great 
discrepancies which we find in the analyses of different che- 
mists, is to be accounted for by the various objects they had 
in view, while instituting their experiments ; for instance, in 
the relative degrees of purity and of dryness, and chiefly 
from the presence of other substances, which, though bearing 
an affinity to the body under examination, should neverthe- 
less be considered distinct, as having a different elementary 
composition. By the process of fermentation, the nature of 
sugar becomes entirely altered, and with it are also changed 
and modified the other ingredients which were in combina- 
tion with it — its great characteristic, sweetness, being entirely 
lost. From the experiments of Berzelius, Berard, Gay 
Lussac, and Thenard, it would appear, that in the former 
periods of fermentation, carbonic acid is always disengaged : 
this, however, is not a necessary process. The oxygen which 
is used, goes into combination, and not to produce carbonic 
acid gas. The author is of opinion, whatever the results of 
Rosin’s and Saussure’s experiments may be to the contrary, 
that acetification depends almost exclusively upon an internal 
* The following report is extracted from the Meeting of the Society in the 
Athenaeum, June 3rd, 1837. 
