ADDRESS. 9 
have discharged the same necessary function of removing refuse and 
providing food for successive generations of plants and animals during the 
past periods of the world’s history ; and it is interesting to think that 
organisms as simple as can well be conceived to have existed when life first 
appeared upon our globe have, in all probability, propagated the same 
lowly but most useful offspring during the ages of geological time. 
Pasteur’s labours on fermentation have had a very important influence 
upon surgery. I have been often asked to speak on my share in this 
matter before a public audience ; but I have hitherto refused to do so, 
partly because the details are so entirely technical, but chiefly because E 
have felt an invincible repugnance to what might seem to savour of self- 
advertisement. The latter objection now no longer exists, since advancing 
years have indicated that it is right for me to leave to younger men the 
practice of my dearly loved profession. And it will perhaps be expected 
that, if I can make myself intelligible, I should say something upon the 
subject on the present occasion. 
Nothing was formerly more striking in surgical experience than the 
difference in the behaviour of injuries according to whether the skin was 
implicated or not. Thus, if the bones of the leg were broken and the 
skin remained intact, the surgeon applied the necessary apparatus without 
any other anxiety than that of maintaining a good position of the fragments, 
although the internal injury to bones and soft parts might be very severe. 
If, on the other hand, a wound of the skin was present communicating 
with the broken bones, although the damage might be in other respects 
comparatively slight, the compound fracture, as it was termed, was one of 
the most dangerous accidents that could happen. Mr. Syme, who was, I 
believe, the safest surgeon of his time, once told me that he was inclined to 
think that it would’ be, on the whole, better if all compound fractures of 
the leg were subjected to amputation, without any attempt to-save the 
limb. What was the cause of this astonishing difference? It was clearly 
_ in some way due to the exposure of the injured parts to the externa} 
world. One obvious effect of such exposure was indicated by the odour of 
the discharge, which showed that the blood in the wound had undergone 
putrefactive change by which the bland nutrient liquid had been converted 
into highly irritating and poisonous substances. I have seen a man with 
compound fracture of the leg die within two days of the accident, as 
plainly poisoned by the products of putrefaction as if he had taken a fatal 
dose of some potent toxic drug. 
An external wound of the soft parts might be healed in one of two 
ways. If its surfaces were clean cut and could be brought into accurate 
apposition, it might unite rapidly and painlessly ‘by the first intention.’ 
This, however, was exceptional. Too often the surgeon’s efforts to obtain 
primary union were frustrated: the wound inflamed and the retentive 
stitches had to be removed, allowing it to gape ; and then, as if it had 
been left open from the first, healing had to be effected in the other way 
