f that seed which fell into good ground, and brought forth
fruit, some thirty fold, some sixty fold, some an hundred fold? On
examination, this notion of organic growth turns out to be more than a
mere surmise. In the year 1680, when the microscope was still in its
infancy, Leeuwenhoek turned the instrument upon this substance, and
found it composed of minute globules suspended in a liquid. Thus
knowledge rested until 1835, when Cagniard de la Tour in France, and
Schwann in Germany, independently, but animated by it common thought,
turned microscopes of improved definition and heightened powers upon
yeast, and found it budding and sprouting before their eyes. The
augmentation of the yeast alluded to above was thus proved to arise
from the growth of a minute plant now called Torula (or Saccharomyces)
Cerevisiae. Spontaneous generation is therefore out of the question.
The brewer deliberately sows the yeast-plant, which grows and
multiplies in the wort as its proper soil. This discovery marks an
epoch in the history of fermentation.

But where did the brewer find his yeast? The reply to this question
is similar to that which must be given if it were asked where the
brewer found his barley. He has received the seeds of both of them
from preceding generations. Could we connect without solution of
continuity the present with the past, we should probably be able to
trace back the yeast employed by my friend Sir Fowell Buxton to-day to
that employed by some Egyptian brewer two thousand years ago. But you
may urge that there must have been a time when the first yeast-cell
was generated. Granted--exactly as there was a time when the first
barley-corn was generated. Let not the delusion lay hold of you that
a living thing is easily generated because it is small. Both the
yeast-plant and the barley-plant lose themselves in the dim twilight
of antiquity, and in this our day there is no more proof of the
spontaneous generation of the one, than there is of the spontaneous
generation of the other.

I stated a moment ago that the fermentation of grape-juice was
spontaneous; but I was careful to add, in what sense spontaneous will
appear more clearly by-and-by.' Now this is the sense meant. The
wine-maker does not, like the brewer and distiller, deliberately
introduce either yeast; or any equivalent of yeast, into his vats; he
does not consciously sow in them any plant, or the germ of any plant;
indeed, he has been hithe