arrangement in sixes existed only in the worthy Dutchman's imagination.

It was very soon made out that these yeast organisms, to which Turpin
gave the name of _Torula cerevisioe_, were more nearly allied to the
lower Fungi than to anything else. Indeed Turpin, and subsequently
Berkeley and Hoffmann, believed that they had traced the development of
the _Torula_ into the well-known and very common mould--the _Penicillium
glaucum_. Other observers have not succeeded in verifying these
statements; and my own observations lead me to believe, that while the
connection between _Torula_ and the moulds is a very close one, it is of
a different nature from that which has been supposed. I have never been
able to trace the development of _Torula_ into a true mould; but it is
quite easy to prove that species of true mould, such as _Penicillium_,
when sown in an appropriate nidus, such as a solution of tartrate of
ammonia and yeast-ash, in water, with or without sugar, give rise to
_Toruloe_, similar in all respects to _T. cerevisioe_, except that they
are, on the average, smaller. Moreover, Bail has observed the development
of a _Torula_ larger than _T. cerevisioe_, from a _Mucor_, a mould allied
to _Penicillium_.

It follows, therefore, that the _Toruloe_, or organisms of yeast, are
veritable plants; and conclusive experiments have proved that the power
which causes the rearrangement of the molecules of the sugar is
intimately connected with the life and growth of the plant. In fact,
whatever arrests the vital activity of the plant also prevents it from
exciting fermentation.

Such being the facts with regard to the nature of yeast, and the changes
which it effects in sugar, how are they to be accounted for? Before
modern chemistry had come into existence, Stahl, stumbling, with the