ion. We may not be able to trace their line
of parentage, for our imperfect vision cannot follow the motes which
play in the sunbeam, nor track them from their birth-place to their
final home. But we know that they must be deposited in every layer of
dust that falls from the atmosphere, that they must be inhaled with
every breath which an animal draws, and be swallowed with every morsel
and drop of its food. The experiments which seem to prove that living
beings may be produced from pure inorganic matter are all explicable on
the supposition, that adequate precautions were not taken to exclude
every animal and germ capable of development from the substances
experimented upon, and from the air which was admitted into the
apparatus. On this ground, the experiments of Crosse and Weekes, cited
by our author, have been quite generally rejected by scientific men, as
hardly deserving of notice. We learn that the former was "discouraged by
the reception of his experiments," and "soon discontinued them";--with
good reason, for it does not appear from our author's account, that he
adopted any precautions at all. Mr. Weekes seems to have been a little
more cautious, and the consequence was, that he did not observe any
appearance of life among the substances experimented upon for "eleven
months," at the end of which time we may reasonably suppose, that his
precautions ceased to have perfect effect. The only experiment, in which
adequate means to guard against causes of error were taken, was that of
Professor Schulze, of Berlin, which had a contrary result. We extract
Mr. Owen's account of it.

"He filled a glass flask half full of distilled water, in which
were various animal and vegetable substances: he then closed it
with a good cork, through which were passed two glass tubes, bent
at right angles, the whole being air-tight: it was next placed in a
sand bath, and heated until the water boiled violently. While the
watery vapor was escaping by the glass tubes, the Professor
fastened at each end an apparatus which chemists employ for
collecting carbonic acid: that at the one end was filled with
concentrated sulphuric acid, and the other with a solution of
potash. By means of the boiling heat, it is to be presumed that
every thing living, and all germs in the flask or in the tubes were
destroyed; whilst all access was cut off by the sulphuric acid on
the one side, and b