forming the compound globules of which Leeuwenhoek speaks, though the
constancy of their 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 cerevisiae_, 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 _Torulae_, similar in all respects to _T.
cerevisiae_, except that they are, on the average, smaller. Moreover,
Bail has observed the development of a _Torula_ larger than _T.
cerevisiae_, from a _Mucor_, a mould allied to _Penicillium_.

It follows, therefore, that the _Torulae_, 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