AND THE HEALING ART 495 



and animals are resolved into simpler compounds fitted for assimilation by 

 new living forms. Without their aid the world would be, as Pasteur said, 

 encombre de cadavres. They are essential not onl}^ to our well-being, but to our 

 very existence. Similar microbes must liave 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 probabilitv, pro- 

 pagated 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 I 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 difterence 

 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 an}' 

 attempt to save the limb. What w^as the cause of this astonishing difterence ? 

 It was clearly in some way due to the exposure of the injured parts to the external 

 world. One obvious effect of such exposure was indicated by the odour of the 

 discharge, which showed that the blood in the wound had mulergone jnitrefac- 

 tive change by which the bland nutrient licpiid 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. 



