THE HORSE’S FOOT. 
543 
old, if the necrosis has progressed and is still increasing, a se¬ 
rious operation becomes necessary. If the necrosis is recent, one 
must be guided by external indications. Notwithstanding, (Re- 
mault remarks,) one should not be too hasty, as the animal must 
necessarily be laid up for several months afterwards. It is often 
sufficient, in a recently punctured wound, in order to avoid compli¬ 
cations, to modify the condition of the fibrous tissues in the whole 
extent of the lesion, by applying substances simply antiseptic, or 
still better, slightly caustic. Key employs the cold bath, in which 
he dissolves a pound of sulphate of copper for ten or fifteen 
quarts of water; by this means he has secured the speedy recov¬ 
ery of severe punctured wounds. For a long time, and with the 
same object, we have been using a mixture of equal parts of sul¬ 
phate of copper and sulphate of iron, having first hollowed the 
foot downwards round the seat of the puncture, and the sole be¬ 
ing pared down as thin as could be borne. 
H. Bouley prefers the application of pulverized corrosive 
sublimate ; after tracing the wound to its bottom, he fills it well 
with the powder. This remedy was already recommended by 
Solleysel, who used it in caries of thejos pedis. Other practitioners 
prefer phenic acid, and claim for it great advantages. By the 
actions of the caustics upon the fibrous tissues exposed to ne¬ 
crosis, or already in that condition, a double salutary result is ob¬ 
tained ; first, the transformation of the part, which is the seat of 
a progressing gangrene, into a chemical eschar; and, again, pro¬ 
moting the more active vascularization of the surrounding parts, 
and consequently their increased power of healthy reaction ; con¬ 
ditions twice favorable to the sloughing of the eschar, and the 
process of repair following it. 
When the wound has reached the os pedis, and this has be¬ 
come carious, a portion of the sole is removed, so that the sup¬ 
puration can escape, the bone is scraped off, and a dressing of 
carbolized alcohol applied, kept on by a thin shoe or slipper, 
with tin plates. 
When there is a fistulous wound > through which synovia es¬ 
capes, yet not purulent, caustics are recommended. Solleysel 
preferred these, but blacksmiths used them so carelessly that they 
