he disease has
shown itself in this mysterious way, but where a strict examination
has revealed its true parentage and extraction. Is it, then,
philosophical to take refuge in the fortuitous concourse of atoms as a
cause of specific disease, merely because in special cases the
parentage may be indistinct? Those best acquainted with atomic
nature, and who are most ready to admit, as regards even higher things
than this, the potentialities of matter, will be the last to accept
these rash hypotheses.

The Germ Theory applied to Surgery.

Not only medical but still more especially surgical science is now
seeking light and guidance from this germ theory. Upon it the
antiseptic system of Professor Lister of Edinburgh is founded. As
already stated, the germ theory of putrefaction was started by
Schwann; but the illustrations of this theory adduced by Professor
Lister are of such public moment as not only to justify, but to render
imperative, their introduction here.

Schwann's observations (says Professor Lister) did not receive the
attention which they appeared to me to have deserved. The
fermentation of sugar was generally allowed to be occasioned by the
_Torula cerevisiae_; but it was not admitted that putrefaction was due
to an analogous agency. And yet the two cases present a very striking
parallel. In each a stable chemical compound, sugar in the one case,
albumen in the other, undergoes extraordinary chemical changes under
the influence of an excessively minute quantity of a substance which,
regarded chemically, we should suppose inert. As an example of this
in the case of putrefaction, let us take a circumstance often
witnessed in the treatment of large chronic abscesses. In order to
guard against the access of atmospheric air, we used to draw off the
matter by means of a canula and trocar, such as you see here,
consisting of a silver tube with a sharp-pointed steel rod fitted into
it, and projecting beyond it. The instrument, dipped in oil, was
thrust into the cavity of the abscess, the trocar was withdrawn, and
the pus flowed out through the canula, care being taken by gentle
pressure over the part to prevent the possibility of regurgitation.
The canula was then drawn out with due precaution against the reflux
of air. This method was frequently successful as to its immediate
object, the patient being relieved from the mass of the accumulated
fluid, and experiencing no inconvenience from the operation.