CHAPTER IV. 

 GANGRENE. 



SYNONYMS. — Necrosis, mortification, sphacelus. 



DEFINITION. — Gangrene is the death of a consider- 

 able area of tissue due to arrested nutrition. The word "gan- 

 grene" in modern surgery is used largely to designate the 

 death of superficial, soft parts of the body, in distinction to 

 "necrosis" which is applied to death in bone tissue or in the 

 internal organs. The arbitrary use of these words is, how- 

 ever, admissible so long as they are applied to the death of 

 tissues en masse. The word "ulceration" must be applied 

 to molecular disintegration, and "sphacelus" to death of 

 unusually large areas, such as an entire limb. 



Death of circumscribed areas of tissue is a very common 

 condition in domestic animals. It is encountered at every 

 turn, in many phases, and in all the various degrees of extent 

 and seriousness. No domestic animal is exempt from this 

 morbid process, but those used for working purposes are par- 

 ticularly predisposed to both the superficial and the organic 

 forms, owing to the greater liability of sustaining the in- 

 juries and diseases upon which gangrene so largely depends 

 in animals. 



ETIOLOGY. — Gangrene, or .necrosis, in a word, is ar- 

 rested nutrition due to obturation of the nutrient vessels of a 

 given part. The causes of gangrene are largely physical 

 causes — vascular obstructions — but it may also result from 

 inflammation of extreme intensity (mycotic gangrene). In 

 animal surgery, the causes are chiefly determining causes, al- 

 though gangrene may be predisposed by both local and sys- 

 temic debility. A local area affected with a pre-existing dis- 

 ss 



