ANTISEPSIS AND ASEPSIS. 67 



precautions, there is no danger. The doses used were fifteen to 

 seventy -five minims of a 2 per cent, solution of cocaine for the horse 

 or ox. For dogs fifteen minims should not be exceeded. Solution 

 of stovaine (5 per cent.), dog, M. 20 to M. 30 ; Cat, M. 10 to M. 20 ; 

 horse, 7>j to ojjss. 



IV.— ANTISEPSIS AND ASEPSIS. 



"During the first half of the last century infection of exposed 

 wounds was attributed to impure and exhausted air, especially to 

 the hospital atmosphere and to air charged with the miasma of putre- 

 faction. Pasteur and Tyndall corrected the truth of this idea, and 

 showed that it is not the air itself which has injurious properties, 

 but only the germs it carries in suspension. Sterile organic fluids 

 exposed to the atmosphere immediately begin to ferment, but pro- 

 vided they be kept from contact with all but optically pure air 

 filtered through cotton wool they undergo no change. It was there- 

 fore concluded that decomposition and putrefaction are due to little 

 animate bodies, suspended in the atmosphere, — i.e. germs or microbes 

 — which under favourable conditions break down organic substances. 

 Save for micro-organisms there would be no decomposition and no 

 putrefaction. Extending the logical process, Lister was of opinion 

 that the same changes went on in injured tissues exposed to the 

 action of air as occurred in organic liquids. Septic changes in 

 wounds therefore represent a kind of fermentation. 



In 1865 Lister, inspired by Pasteur's work on fermentation, began 

 those experiments which eventuated in the formulation of his " anti- 

 septic method " ; while in 1870 Guerin, following up the same work 

 and that of Tyndall, invented his surgical dressing. 



Guerin applied to wounds the experimental conditions necessary 

 for preserving organic materials from change when in contact with 

 the air, shielding the injured tissues by thick layers of cotton wool. 

 Lister, on the other hand, sought to destroy microbes present in the 

 wound or introduced during operation, by means of chemical 

 substances. Lister first rendered the wound aseptic and afterwards 

 protected it by a germicidal barrier. 



At first Guerin did not seek primary union of the wound, only 

 attempting to reduce the discharges and to avoid infection. Bleeding 

 having ceased, he washed the wound with tepid water, afterwards 

 with a mixture of water and camphorated alcohol. In some cases 

 he sutured the wound and cut the threads short, covering the parts 

 with several layers of wadding. In extensive operations on the 



