GANGRENE, OB MOBTIFICATION. 473 



nonpoisonous dry dressing powder, such as is used in ordinary open 

 wounds, as tannic acid 8 parts and iodoform 1 part, or a salve made 

 of this powder and a sufficient quantity of vaseline. When sloi^gh- 

 ing of the tissues takes place the wounds should be cleansed with a 

 warm 3 per cent solution of carbolic acid, all loose fragments of tissue 

 removed, and either a dry antiseptic dressing powder or carbolated 

 vaseline ointment applied to exclude the air. Granulation tissue 

 (proud flesh) should be controlled by the application of silver nitrate 

 in the form of a caustic pencil. 



Burns due to mineral acids may be first treated by flushing the 

 parts with a copious quantity of cold water or by the application of 

 whiting or chalk. Either use a large quantity of water at the start or 

 use the chalk first, then wash with water. If the irritant has been a 

 caustic alkali, such as potash, lye, ammonia, or soda, then vinegar 

 should be the first application. Stahl's liniment is probably the best 

 general application for all burns for the first week ; then this should 

 be followed by the ordinary antiseptic wound dressings. 



GANGRENE. 



Gangrene, or mortification, denotes the death of the affected part, 

 and is mostly found attacking soft tissue near the surface of the 

 body. Gangrenous areas may occur as a result of shutting off their 

 blood supply. Constitutional diseases, such as ergotism, anthrax, and 

 septicemia, predispose to gangrene. As external causes we have acids 

 and alkalies, freezing and burning, contusions and continuous pres- 

 sure that interrupt the circulation. There are two forms of gan- 

 grene — dry and moist. Dry gangrene is most often seen in horses 

 from continuous lying down (decubitus) or from uneven pressure of 

 some portion of the harness. 



Symftoms. — There is a lack of sensation due to the death of nerves. 

 In dry gangrene the skin is leathery and harsh, while in moist gan- 

 grene the tissues are soft, wrinkled, and friable; the hair is dis- 

 turbed, and the skin is usually moist and soapy and sometimes cov- 

 ered with blebs. The tissue surrounding the moist gangrenous patch 

 is usually inflamed, swollen, and hot, but this is less noticeable in the 

 case of dry gangrene. Moist gangrene often spreads and involves 

 deeper tissue, sheaths of tendons and joints producing septic syno- 

 vitis or septic arthritis leading to pyemia and death. Dry gangrene 

 is seldom dangerous, but the rapidity of its spread will indicate its 

 virulence. 



Treatment. — The preventive treatment consists in avoiding all the 

 influences that tend to disturb the nutrition of the tissues, such as 

 excessive cold or heat or continuous pressure. Gangrene following 

 decubitus may be prevented by using soft bedding and frequently 

 turning the animal from one side to the other. In dry gangrene moist 



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