TREATMENT OF CANKER. 1093 



powder, it forms a dry scab, checks extension of the growth, exerts 

 an intense drying action, and checks proliferation and secretion in 

 the reticular tissue. Sometimes the process starts again under the 

 dry crust, which therefore requires to be carefully examined during 

 the next few days. Acids, particularly fuming nitric acid, can also 

 be used, but their application requires care, whilst their action is 

 difficult to control and certainly not more satisfactory than that 

 of nitrate of lead. Experiments with sulphuric acid in the treatment 

 of grease suggest the advisability of trying it in canker. Formalin 

 solution, on account of its caustic, antiseptic, and drying action, is 

 of great value. Frohner recommended the cautious use of the officinal 

 40 per cent, solution of formic aldehyde, applied with a brush. This, 

 however, is much too energetic, and 5 to 10 per cent, or even weaker 

 solutions are preferable ; if necessary, their application can be repeated. 

 Hell, who used formalin extensively, prefers the 5 per cent, solution, 

 as he has seen severe results from using the 10 per cent. He applies 

 the solution on tampons of tow. When the growth is not severe, 

 and the secretion is alone troublesome, calomel, liquor ferri perchlor, 

 1 per cent. ; chloride of zinc, 10 per cent. ; tincture of iodine, tar, 

 &c, may be tried. Each has at some time been strongly recommended. 

 Whichever be employed, a pressure dressing is always necessary. 

 The actual cautery has been used to destroy the diseased tissue 

 and excite repair, but requires supplementing with some antiseptic 

 or astringent. 



As a rule, treatment is commenced by removing the horn, and, 

 if the hoof be very dry and hard, by immersing the foot in a warm 

 foot-bath. All undermined horn must be removed. This is a sine 

 qua non in treatment. The foot is then soaked in a disinfectant, 

 such as carbolic, chloride of zinc, or sublimate solution. After one 

 or two hours' immersion, and after repeatedly washing the diseased 

 part whilst the foot is in the bath, the material selected is applied 

 and a dressing put on. Next day this is renewed, and if the process 

 have extended farther, the undermined horn is at once removed ; 

 otherwise, if the surface remain dry, a fresh dressing is applied. 



At first the dressing is renewed daily. To check excessive pro- 

 liferation, the parts are dressed with nitrate of lead, and a pressure 

 dressing of tow tampons tightly applied. In disease of the frog, 

 bars, and sole, a shoe provided with a removable iron covering, or 

 a plaster cast, will be found exceedingly useful. To prepare the 

 latter, the hoof is filled with freshly -prepared plaster of Paris, mixed 

 with chopped tow or hemp, to render it less friable, and the whole 

 allowed to harden. When applying it, the sole should be covered 



