when the contents were boiling,
showed that in that case no life was produced. He declared, and
correctly too, as we now know, that Needham's methods did permit of the
introduction of something from without. The controversy went to sleep
again until the discovery of oxygen by Priestley in 1774. When it had
been shown that oxygen was essential to the existence of all forms of
life, the question arose as to whether the boiling of the organic fluids
in the earlier experiments had not expelled all the oxygen and thus
prevented the existence and development of any life.

In the further experiments which this query gave rise to, we meet with
another illustrious Catholic name, that of Theodor Schwann, better known
as the originator of that fundamental piece of scientific knowledge, the
cell-theory. Theodor Schwann (1810-1882) was born at Neuss and educated
by the Jesuits, first at Cologne, afterward at Bonn. After studying at
the Universities of Wuerzburg and Berlin he became professor in the
Catholic University of Louvain, where his name was one of the principal
glories of this now wrecked seat of learning. Thence he went as
professor to Liege, where he died. He was, says his biography in the
_Encyclopaedia Britannica_, "of a peculiarly gentle and amiable character
and remained a devout Catholic throughout his life." Schwann's
experiments tended to show that the introduction of air--of course
containing oxygen--did not lead to the production of life, if the air
had first been thoroughly sterilised. It was thought that this question
had been finally answered, when it was reopened by Pouchet, in 1859. He
was a Frenchman, the director of the Natural History Museum of Rouen,
but as to his religious views I have no information. It is quite
probable, however, that he was a Catholic. Pouchet and all on his side
were finally--so far as there can be finality in such a matter--disposed
of by Pasteur, of whose distinction as a man of science and devoutness
as a Catholic nothing need be said.

It is quite unnecessary to devote any consideration here to the
character of Pasteur's experiments, for they have become a matter of
common knowledge to all educated persons. Let it suffice to say that
they were on the lines first laid down by Redi and greatly elaborated by
Spallanzani, namely the exclusion from the fluids or other substances
under examination of all possible contamination by minute organisms in
the air. Spallanzani knew nothing