124 M. Kekulé on Derivatives of Suecinic Acid. 
2nd, The yeast reacts on itself when the sugar has been com- 
pletely destroyed. 
3rd. The effect produced by the yeast on itself is not pro- 
portional to the weight of the yeast. 
The author assumes that the globules formed by the fermen- 
tation of the sugar cannot attain their complete development for 
want of sufficient sugar, and that the young globules needing 
this nourishment live at the expense of the parent globules,— 
which produces a secondary fermentation, or the yeast destroys 
itself. 
Lastly, M. Pasteur speaks of the application of some of the 
results to the composition of fermented liquors. 
Since glycerme and succinic acid are constant products of 
the alcoholic fermentation, they ought to be fouhd in wine, 
beer, cider, &c. This the author has already shown to be the 
case. 
He terminates his memoir by the following passage, contain- 
ing the fundamental conclusion which he draws from his im- 
portant researches :—‘“ As to the interpretation of the whole of 
the new facts which I have met with in my researches, I think 
that whoever considers them impartially will see that fermentation 
is a correlative act of life, and of the organization of globules, 
and not of death or the putrefaction of these globules; still less 
does it appear to be a phenomenon of contact, where the trans- 
formation of sugar proceeds in the presence of the ferment with- 
out yielding anything to it, or taking anything from it.” 
Kekulé has described* a mode of preparing the brominated 
derivatives of succinic acid, which is simpler than the methods 
hitherto employed. 
To obtain bibromosuccinic acid, C4 H* Br? 04, he heats in 
sealed tubes (at 150°—180°) twelve parts of succinic acid with 
thirty-three parts of bromine and twelve parts of water. After 
the reaction is complete, the whole mass is changed into small 
greyish crystals, and on opening the tube a large quantity of 
hydrobromic acid escapes. The crystals are purified by washing 
with cold water, solution in boiling water, and treatment with 
animal charcoal. Bibromosuccinic acid is formed in all cases in 
which a small quantity of water is taken, even when the propor- 
tion of bromine is such as to form monobromosuccinic acid. 
Monobromosuccinic acid, C* H° Br 04, is obtained by heating 
succinic acid with bromine and with a larger quantity of water. 
It is purified in a similar manner, but, being more soluble, it 
crystallizes less easily. 
* Bulletin de la Société Chimique, p. 208, 
