408 
ON CANKER. 
Having finished paring, the shoe I generally use is a common 
bar shoe, and sometimes a plain thin-heeled shoe. 
Various are the applications used in canker, and many of them 
with good effect. I generally use sulphuric acid and petroleum, or 
nitrous acid and petroleum, or an ointment composed of bole arme- 
niac two ounces, sulphate of copper two ounces, and alum two 
ounces, with treacle sufficient to form an unguent, to which I occa¬ 
sionally add a little muriatic acid ; giving a moderate degree of 
pressure with splents at every dressing; and, if he can be worked 
under coyer, as in a mill, or in the street^, providing the weather 
will admit, I prefer it to his standing in the stable, being very 
careful, however, to prevent exposure to moisture. 
Canker appears to me to be a disease that is, in certain parti¬ 
culars with respect to its treatment, veiy much like the mange ; 
for if you continue one application, and that perhaps which you 
have succeeded with in many previous cases, for any considerable 
time without good effect, you may be almost certain that you will 
do no good by persevering with the same composition. Even that 
which seems at first to do most good, by a long continuance loses 
all power in correcting the diseased action; but, changing the 
application, you will frequently have the most favourable results. 
I have had but few cases where it has extended to the bones; and 
in most that I have seen, either from the inferior value of the 
animal, or from the. impatience of the owners, it has been deemed 
most prudent to destroy them. In those that have been left for 
treatment I have seen very good effect from the balsam of copaiva 
and tincture of myrrh. 
It is mentioned, I believe, by Mr. Coleman, in his lectures on 
this subject, that seeing , the growth of crust was more than 
usual, he took up both arteries going to the foot; but no advantage 
resulted. He made the same experiments on the veins coming 
from the foot, with the same result. He then divided the vessels 
of the coronary ring, to prevent the determination of blood to that 
part and to the crust, consequently sending more blood to the 
sole, and the result proved favourable; for there was less crust 
formed than before, and horn began to form on the sole. He also 
gives an account of another veterinary surgeon performing the 
same operation, and with a favourable result. I am not aware of 
this practice having become general; but I thought it probable that 
some of the members present might have had recourse to it, and 
shall feel obliged by being permitted to learn the result of their 
experience. 
