818 
DISEASES OE THE FOOT. 
action, formalin 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 difficult to control, and 5 to 10 per cent, 
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 sesquichlorid., 
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 chemical caustic. 
Portions of undermined horn must be removed. This is a sine qua non 
in treatment, and requires no slight dexterity and practice in handling 
the knife. 
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. 
It is not always possible to remove every particle of loose horn at one 
operation, for as soon as bleeding occurs it is no longer safe to proceed, 
and is usually better to wait for a day. The foot is then soaked in a 
disinfectant, such as creolin, 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 further, the undermined horn is at once 
lemoved , otliei wise, it the surface remain dry, a fresh dressing is applied. 
At first the dressing is renewed daily. To check excessive proliferation, 
the parts are dressed with nitrate of lead, and a pressure dressing tightly 
applied. In disease of the frog, bars, and sole, a shoe provided with a 
removable iron covering (see Hollar and Wheatley’s “ Horse-shoeing 
and the Horse’s Foot,” pp. 884 e* seq.), 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 fuable, and the whole allowed to harden. W hen applying it, the 
sole should be covered with tow, so as to press as equally as possible on 
the growing tissues. A well-made shoe fulfils the same purpose. Even 
at a later stage, it is important to renew the dressing every two or’three 
days at least, and to examine the condition of the hoof. Particular 
attention should be directed to the margins of the diseased spot, and 
to the diy scab , if only the slightest trace of grey, greasy material 
is present, it must at once • be ascertained whether the process is 
