48 DISEASE^ OF THE DOMESTIC ANIMALS 



zinc oxide (equal parts) into the ear, and pack loosely with ab- 

 sorbent cotton after each irrigation. Three per cent, phenol, or 

 i to 8,000 corrosive sublimate solution, may be used in place of 

 the boric acid. The diet should be restricted. In mild cases the 

 injection of 50 per cent, aqueous solution of ichthyol is sometimes 

 curative. In the later stages the use of astringent solutions is ad- 

 visable, as a 2 to 4 per cent, solution of silver nitrate, lead acetate or 

 cupric sulphate once daily. The canal should be wiped dry and the 

 boric acid and zinc oxide powder blown in. With a tendency to 

 chronicity one should touch the surface of the canal with stick lunar 

 caustic, after local anesthesia with powdered cocaine. In severe 

 cases the inflammation may lead to caries of the bony canal, when 

 curettement is indicated under general anesthesia. A pill of iron 

 and arsenic (modified Blaud's pill, each gr. v) often assists re- 

 covery, when given three times daily for two or three weeks. 



2. External Canker. — This has no pathological connec- 

 tion whatever with internal canker, but is mentioned on account of 

 its similarity of name. It is an abrasion, ulcer, or fissure on the tip 

 of the external ear caused by trauma or shaking the ears in long- 

 eared dogs. 



Treatment. — The use of a netted cap over the dog's head, 

 bathing the wound in antiseptic solution, and cauterizing it with 

 lunar caustic, or the cutting away of the diseased surface and 

 suture of fissures with fine silver wire, constitute the proper treat- 

 ment. Cropping the ears is the radical method of cure, if other 

 means fail. 



Canker of Feet in Horses. 



This condition is probably due to some special organism — 

 possibly one of the fungi. It is characterized by soft, spongy swell- 

 ing of the frog with fetid, cheesy secretion — going on to destruc- 

 tion of the frog and sole of the foot and the production of fungoid 

 growths. 



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