such as sugared water, the new globules live at the ex-
pense of substances which the older globules have
allowed to diffuse into the liquid. All are famished and
then the young consume the old. It is this work of
diffusion and of exhaustion of globules already formed
in order to feed the young, which caused the diminishing
weight of the yeasts sown by Thénard in the sugared
water in the experiments cited above, and which has
led to the belief that the yeast is destroyed in fermenting
the sugar. In reality, there were not enough of the
new globules formed to compensate for the loss of weight
which the old globules underwent as the result of the
diffusion but if we add to the weight of the globules the
weight of the soluble organic matter which the filter does
not retain, but which we can find and estimate in the
liquid, we see that this total weight always increases
during the fermentation, because there is always a little
sugar which becomes yeast.

In proportion as the fermentation is accomplished
under better conditions and the yeast is less exhausted
toward the end, the increase in weight is more notable.
We are aware of this from the fact that the yeast con-
tinues to give off carbonic acid at the expense of its own
tissues for some time after all the sugar has disappeared
from the liquid which bathes it. We would say to-day
that it consumes the reserve food which it has made,
for it is a provident little cell which stores up in a time
of plenty for a time of famine. How is it possible not to
see that all this is a question not of decomposition and
of death, but, on the contrary, of development and
of life?

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