tissue laid bare by the knife shall be defended from germs; that if
they fall upon the wound they should be killed as they fall. With
this in view he showers upon his exposed surfaces the spray of dilute
carbolic acid, which is particularly deadly to the germs, and he
surrounds the wound in the most careful manner with antiseptic
bandages. To those accustomed to strict experiment it is manifest
that we have a strict experimenter here--a man with a perfectly
distinct object in view, which he pursues with never-tiring patience
and unwavering faith. And the result, in his hospital practice, as
described by himself, has been, that even in the midst of abominations
too shocking to be mentioned here, and in the neighbourhood of wards
where death was rampant from pyaemia, erysipelas, and hospital
gangrene, he was able to keep his patients absolutely free from these
terrible scourges. Let me here recommend to your attention Professor
Lister's 'Introductory Lecture before the University of Edinburgh,'
which I have already quoted; his paper on The Effect of the Antiseptic
System of Treatment on the Salubrity of a Surgical Hospital;' and the
article in the 'British Medical Journal' of January 14, 1871.

If, instead of using carbolic acid spray, he could surround his wounds
with properly filtered air, the result would, he contends, be the
same. In a room where the germs not only float but cling to clothes
and walls, this would be difficult, if not impossible. But surgery is
acquainted with a class of wounds in which the blood is freely mixed
with air that has passed through the lungs, and it is a most
remarkable fact that such air does not produce putrefaction. Professor
Lister, as far as I know, was the first to give a philosophical
interpretation of this fact, which he describes and comments upon
thus:

I have explained to my own mind the remarkable fact that in simple
fracture of the ribs, if the lung be punctured by a fragment, the
blood effused into the pleural cavity, though freely mixed with air,
undergoes no decomposition. The air is sometimes pumped into the
pleural cavity in such abundance that, making its way through the
wound in the pleura costalis, it inflates the cellular tissue of the
whole body. Yet this occasions no alarm to the surgeon (although if
the blood in the pleura were to putrefy, it would infallibly occasion
dangerous suppurative pleurisy). Why air introduced into the pleural
cavity through a