y the potash on the other. The apparatus was
then exposed to the influence of summer light and heat; at the same
time, there was placed near it an open vessel, with the same
substances that had been introduced into the flask, and also after
having subjected them to a boiling temperature. In order to renew
constantly the air within the flask, the experimenter sucked with
his mouth several times a day the open end of the apparatus, filled
with the solution of potash, by which process the air entered his
mouth from the flask through the caustic liquid, and the
atmospheric air from without entered the flask through the
sulphuric acid. The air was of course not at all altered in its
composition by passing through the sulphuric acid in the flask; but
all the portions of living matter, or of matter capable of becoming
animated, were taken up by the sulphuric acid and destroyed. From
the 28th of May until the beginning of August, Professor Schulze
continued uninterruptedly the renewal of the air in the flask,
without being able, by the aid of the microscope, to discover any
living animal or vegetable substance; although, during the whole of
the time, observations were made almost daily on the edge of the
liquid; and when, at last, the Professor separated the different
parts of the apparatus, he could not find in the whole liquid the
slightest trace of _Infusoria_ or _Confervae_, or of mould; but all
three presented themselves in great abundance a few days after he
had left the flask standing open. The vessel which he placed near
the apparatus contained on the following day _Vibriones_ and
_Monads_, to which were soon added larger Polygastric _Infusoria_,
and afterwards _Rotifera_."--pp. 32, 33.

For readers who are not familiar with these subjects, it may be well to
mention, that the weight of authority is decidedly against this doctrine
of spontaneous generation. It is rejected by Mueller, who ranks among
the first physiologists of Germany; by Ehrenberg, one of the most
distinguished microscopists in the world; and by Owen, who stands at the
head of the school of comparative anatomy in England, if not in Europe.
The remark made by Cuvier, more than thirty years ago, is still true at
the present day, that, "although the impossibility of spontaneous
generation cannot be absolutely demonstrated, yet all