TUMOUR TAKEN FROM THE BACK OF A MARE. 
77 5 
August last my attention was again directed to it, as it had 
become so much larger. I then found it about half the size 
it now is, loose and unconnected ; and, although the mare 
was ridden every day, she continued not to manifest the 
slightest inconvenience from the tumour, neither was there 
any swelling around it. She continued her work up to the 
present time, when her owner going away for a little while, 
he wished me to remove it, as it looked unsightly, which, of 
course, I did. 
I thought it might prove a thickened state of the cellular 
tissue merely, as it was situated immediately beneath the 
skin and over the muscles of the back, being some distance 
from any bony structure. After the operation the lips of 
the wound were drawn together by a few sutures, and the 
wound is healing fast. 
I remain, dear Sir, 
Yours truly, &c. 
Professor Varnell. 
REMARKS ON THE ABOVE BY PROEESSOR VARNELL. 
The tumour referred to in the above communication 
must not be considered as true bone, which, from its hardness 
and weight, it might be taken for. It is composed of a 
fibrinous stroma, in which is deposited a quantity of earthy 
matter, but is unlike true bone in being wholly destitute of 
the Haversian system of canals for the passage of blood¬ 
vessels. 
I have met with similar formations, when dissecting, in 
various parts of the body. I have found them in the coats of 
large arteries, in the subperitoneal tissue, but more especially 
in the subcutaneous tissue of the old, ill-used ass. In these 
poor animals, depositions of this nature are more often found 
in such parts as have been exposed to injury from the saddle, 
collar, or some other portion of the harness, or from what is 
worse, the unmerciful blows inflicted by the driver, or the 
sharpened end of a nail, so commonly used to compel them 
to perform their work. The continued irritation thus in¬ 
duced results in the effusion of lymph and calcareous matter 
in solution, into the areolar tissue; the former becoming a sort 
of matrix for the latter to become imbedded in, in a solid 
form. These deposits, which are slowly produced, after a 
time become condensed, and from the almost continued 
motion of the skin over the fascia they are often partially or 
wholly detached from the surrounding cellular tissue. 
