EXCISION OF A LARGE MELANOTIC TUMOUR IN A MARE. 53 
For a few days after the operation the animal suffered slightly 
from fever, but this disappeared as soon as suppuration was fairly 
established. The mare was in her usual health and took her 
ordinary feeds at the end of the fortnight. 
The pus which flowed from the wound for the first few days 
was black, but it soon became white. The black hue arose evi- 
dently from my having left some melanotic portions of the tumour, 
which were brought away by the suppuration. This circumstance 
did not, however, prevent the cicatrization from being complete. 
I must now recur to a case which struck me at the time as being 
very curious, and of great practical interest. 
A mare was brought to me having several melanotic tumours 
about the tail, some of which were soft, and others ulcerated. I 
amputated the tail. When the operation was terminated, I perceived 
that a deep tumour had been divided by the knife, which formed 
a portion of the stump. The stump of the tail was already very 
short, and therefore I did not amputate it any further, but con- 
tented myself with cauterizing the part in the same manner as if I 
had wished to stop hemorrhage. The scar came off, and I then 
perceived a secretion of black pus, arising doubtless from the parts 
of the divided melanosis. Black spots were also perceptible on 
the stump and vestiges of the melanosis, but these spots were 
separated by red fleshy pimples. As the wound gradually cica- 
trized, these pimples spread and increased, while the black spots 
diminished. The pus became gradually lighter and lighter, and, 
at last, quite white. This fact, which was so palpable, shewed 
me plainly that the tumours usually designated melanosis were 
formed of a tissue in which the melanotic matter resides. The 
flakes of this tissue are so close together, that it is scarcely possible 
to detect the melanotic matter, or get any portion of it. There is 
always a melanotic matter found in every animal frame in the cells 
of the tissue, the same as fat is in the adipose tissues. The same 
may be observed with regard to tubercles, encephaloids, and 
scirrhous formations, before the softening and ulceration of these 
morbid productions. 
These productions should, therefore, only be considered as inor- 
ganic when they arrive at a state of ulceration, which is, in fact, 
their death and decomposition. It appears to me quite evident 
that they possess a species of life while they are in a state of cn/- 
cLity, so to speak, and it is wrong to consider them as inorganic 
during the period of their development. 
In this case of melanosis of the tail which I have just mentioned’,, 
the melanotic tissue of the portions which I had neglected to> 
excise ceased to secrete the melanotic matter, and secreted pus 
instead ; which contributed to the formation of a scar which was 
