256 PRINCIPLES OF VETERINARY SURGERY 



3r(l. Pathogenic bacteria are much more viable than 

 the cells of the body, and hence cannot be destroyed with 

 chemical substances that will not also destroy the cells of 

 the body. This fact necessitates the prevention of infec- 

 tion, because when a bacterium has once invaded the tis- 

 sues it cannot easily be destroyed or removed. 



4th. Wound diseases' are prevented by protecting the 

 wound against microbian invasion. This fact was Lister's 

 hypothesis, and it has not been changed to the present day. 

 Although Lister was not as familiar with the nature of the 

 intruding agent as the present-day surgeon, his deductions 

 were correct. He observed and even emphatically recom- 

 mended the execution of the minutest details in preventing 

 the unknown enemy from invading the open trauma. This 

 then unknown enemy was washed from the seat of opera- 

 tion with soap and water and then with solutions of car- 

 bolic acid, the instruments were sterilized, the hands were 

 cleaned, the sutures were immersed for seveiral days in 

 carbolized oil, the air was sprayed with carbolic acid solu- 

 tion and finally, after the sutures were applied, the wound 

 was protected against subsequent infection by covering it 

 with impervious antiseptic dressings. These few words 

 embody the principles of antiseptic surgery of today. It 

 has- changed only in the details which have since emanated 

 from a better understanding of bacteria. Lister paid too 

 much attention to the air and too little to the instruments 

 and hands, but - otherwise there is little to criticise in the 

 technique he recommended. 



5th. Wounds occasionally become infected by way of 

 the circulation, . but that this form of localization is rather 

 rare is now weirknown.." In: veterinary subjects it is-indeed 

 \ rare. Animals "afife'cted. with tuberculosis, glanders, pyae- 

 irria, or septicaemia, and debilitated subjects generally, rhay 

 occasionally sustain wound infections frbni' within but since 



