1915] on Back to Lister 381 



carry in some unexplained way the seeds of death and disease, being 

 one day the doctor's greatest friend and the next his deadhest foe. 



Physicians were quite sure that the acute specific fevers, such as 

 scarlet fever and measles, were carried on the wings of the wind, and 

 few had any doubt that cholera was borne by the same vehicle. 

 Surgeons were equally certain that erysipelas should be placed in the 

 same class as the acute specific fevers, and that the suppuration of 

 wounds depended upon the same agency. It seemed quite ol^vious 

 to anyone who thought about the difference in the behaviour of 

 simple and compound fractures, that is, fractures with unbroken skin 

 and those which are complicated by the presence of a wound. Except 

 for this complication the fractures might be identical, but in pre- 

 antiseptic days, the presence of a wound was almost certain to lead 

 to suppuration of a serious, if not a dangerous nature. 



Old Glasgow students speak of Lister contemplating a simple 

 fracture of the leg ; the muscles torn and pulped, the limb swollen 

 and shiny, black and blue, and pointing out to them that all this 

 destruction of tissue and extravasation of blood would be surely and 

 safely dealt with by the kindly influences of nature ; but that the 

 admission of the air through the smallest wound in the skin would 

 completely change the prospect ; the extravasated blood would soon 

 stink, the injured tissues — bone and muscle — would die, and suppura- 

 tion would take place, which might possibly infect the whole system. 

 It did not enter into the mind of anyone, therefore, to doubt the 

 morbific influence of the air. It was one of those things which 

 appear so obvious that for a time they form the very foundations of 

 belief, such as that the earth is flat and that the sun rises, matters 

 which in more barbarous times laid sceptics open to the rigours of the 

 Inquisition. 



This was still the universal belief when Pasteur's discoveries were 

 made known. Pasteur put the finishing touch to the work of many 

 ol^servers, who, during the first half of the last century, had been 

 striving to find out what there was in the atmosphere which gave 

 rise to fermentations of all sorts, and amongst others to that form of 

 fermentation known as putrefaction. So long as fermentation and 

 putrefaction were looked upon as chemical processes it was natural 

 to suppose that one of the gaseous constituents of the air was the 

 cause. But clear thinkers, like John Hunter, saw that this could not 

 be the case. 



There are two surgical conditions that prove this : — 



1. If a rib be broken and a sharp fragment injure the lung, large 

 quantities of air may pass from the lung into the pleural cavity, but 

 if the lung be healthy, decomposition never occurs in the putrescible 

 fluid that is always present in the pleura in small cpiantity. 



2. If air passes into the cellular tissue of the body, as it some- 

 times does after the same accident, or some other injury of the air 

 passages, large portions of the body may be distended by it to an 



Vol. XXI. (No. 109) 2 c 



