262 PRINCIPLES OF VETERINARY SURGERY 



are "scalp-wounds," that is they are in a hairy environment. 

 If the human hands are difficult to clean what is to be said 

 of the skin of a horse, an ox„or a pig? The skin of these 

 animals are veritable hot-beds for bacteria, and its consti- 

 tution is such as to render its sterilization impossible. Ex- 

 periments have shown that the skin of animals is seldom 

 made aseptic, the latest being those of Pendergast and 

 Linch at the New York State Veterinary College, who have 

 shown by tests of skin taken from ten horses that disinfec- 

 tion cannot be absolutely depended upon to destroy all of 

 the bacteria harbored within it. 



Cleansing of the surgical field or the environs of an ac- 

 cidental wound is accomplished by (i) clipping and then 

 shaving the hair; (2) washing with soap and water; (3) 

 washing with mercuric chloride, 1-500 or even 1-200; and 

 (4) washing with pure alcohol. These processes may be 

 carried out twenty-four hours before the operation, and 

 then the field may be covered with a pack soaked in a weak- 

 er mercuric chloride solution. As the operation begins a 

 second immersion with alcohol may be applied. Ordinarily, 

 however, the execution of these steps just before the opera- 

 tion is satisfactory. 



In the accidental wound, washing, shaving and irrigating 

 the surroundings may prove harmful by washing dirt and 

 hairs into the abrasion. Often the hairs may be left alone 

 for this reason. 



After the wound is sutured the environs are kept dry 

 to prevent microbian growth. If the wound secretions are 

 left to flow over the surroundings, beneath a protective 

 bandage, the bacteria which might have remained harmless 

 upon or within the skin, may grow rapidly and thus gain 

 admission to a wound that was otherwise properly treated. 

 Dryness of the environs is no small part of aseptic treat- 

 ment in veterinary subjects. 



