BEFORE AND AFTER LISTER 171 



infection and suppuration were evils, and avoidable evils, 

 sought by various means to prevent them. But he says 

 "all my efforts [during his work in Glasgow, 1860-69] 

 proved abortive," and then adds significantly "as I could 

 liardly wonder when I believed with chemists generally 

 ' that putrefaction was caused by the oxygen of the air." 



They and he were deeply impressed with the absence of 

 putrefaction in simple fractures when the air and its 

 oxygen had no access to the fracture. In my own lectures, 

 as I often used to express it, "The very best antiseptic 

 dressing is an unbroken skin." In compound fractures 

 on the other hand when the air and its oxygen had access 

 to the lesion, putrefaction always took place and caused 

 a frightful mortality. 



To test this supposed noxious influence of oxygen he 

 devised many experiments, and among them one which 

 may be well called an "experimentum crucis." He filled 

 four flasks one-third full of urine (a quickly putrescible 

 liquid) and drew out the necks to tubes one- twelfth of 

 an inch in diameter. All these tubes were left open. 

 Three of these long necks he bent at various angles down- 

 wards; the fourth was left vertical upwards and also 

 open. He then boiled all four flasks and awaited the re- 

 sult. The air and its oxygen had free access to the urine, 

 being slowly drawn in during the colder night hours and 

 driven out in the warmer daytime. Any supposed "germs" 

 floating in the air, he reasoned, being heavier than air, 

 could not climb up the slanting neck and fall into the 

 liquid. In a short time the urine in the flask with the 

 vertical open neck was decomposed, but the other three 

 flasks, also with open necks but bent downward, remained 

 undecomposed for years! 3 They were finally destroyed 

 by a fire in the laboratory. 



Could there be a more convincing proof that the oxygen 



3 For a fuller account of this interesting experiment with ref- 

 erences see my Animal Experimentation and Medical Progress, 

 pp. 204-205. 



