PRINCIPLES OF VETERINARY SURGERY 293 



Kept for several weeks without careful disinfection, instru- 

 ments and dressings, become genuine vehicles. They be- 

 come re-infected from each subject operated upon, thus be- 

 coming conveyors of exceedingly virulent germs which show 

 an increased virulence with each intervention. Today it 

 has been shown that operations can be performed with im- 

 punity in a septic environment. The contrary condition 

 is, of course, preferable, but "in emergency, let the surgeon 

 learn to create for himself an aseptic operating field in a 

 septic environment." (Reclus) 



The gravity of the disease is equally subordinate to the 

 nature, seat and extent of the wound. Other things being 

 equal, wounds which are deep, anfractuous, or the result 

 of crushing, are infinitely more serious than those made 

 with sharp instruments. Then, again, wounds affecting 

 important organs or ducts may be exceptionally serious. 

 Wounds of the urethra are often fatal ; those of Steno's duct 

 may cause death from loss of saliva, and lacerations of the 

 udder may provoke a lacteal fistula of prolonged duration. 



The character of the instrument inflicting the wound 

 needs also to be taken into account. If it is aseptic or only 

 the conveyor of benign germs the wound will behave as an 

 aseptic trauma. Formidable complications may, on the con- 

 trary, supervene if the instrument inflicting the wound, hav- 

 ing been previously soiled, deposits pyogenic or other septic 

 organisms into 'it. 



The physiognomy of a wound may also be modified in a 

 very perceptible manner by the state of resistance or en- 

 feeblement offered by the individual. The condition of the 

 wounded animal has a manifest influence on the evolution 

 of the lesion of which it is the bearer. This important point 

 which was all but known fifty years ago, has been elucidated 

 only by scientists of the French school. Not only does the 

 state of the wounded animal direct the trauma along a 



