MELANOSIS AND OSSIFICATION. 
391 
undoubted proofs, by the records of many cases ; and it will be 
recollected that, in the one related by me, the tumour on the thigh 
was observed when the subject of it was a filly, and that it re- 
mained insensitive and stationary for many years. 
Sometimes, however, one of these bodies enlarges rapidly, and 
the adjacent glands and textures become involved in this morbid 
action : the black deposition goes on so quickly, that, in the space of 
a few months, it amounts to many pounds in weight. The largest 
tumour of this description I remember to have heard of weighed 
36 lbs. These tumours have never been known to terminate 
in resolution, but a softening and something similar to the suppu- 
rative process, occasionally occurs ; they then discharge a black and 
very offensive matter, and ulcerate superficially, the investing in- 
tegument sloughing more than the substance beneath. Under 
these circumstances, there is much suffering and constitutional dis- 
turbance. This morbid action is frequently, I believe, induced in 
the otherwise quiescent body by mechanical irritation, such as a 
blow, friction, or the application of irritants to the part; hence, in 
forming a 
Prognosis , — Attention should be especially directed to the situ- 
ation of the tumours. If they are found existing in exposed parts 
of the body, or having connexion with those designed for frequent 
motion, these are circumstances somewhat unfavourable. 
If emaciation should co-exist without apparent cause in an ani- 
mal affected with ever so small an external melanoid tumour, fears 
may be justly entertained that larger deposits exist internally 
which produce this appearance ; for it has been invariably observed 
that these deposits never exist in one part or structure alone, and 
that the presence of one externally is, but too frequently, the sure 
indication of the existence of others internally. 
In the great majority of melanotic cases, tumours are generally 
seen under the skin, covering the anus, vulva, and hairless portion 
of the dock ; and, as they are usually numerous and small here, 
the excision of one, which, in this situation, may be safely and 
readily done, will be a good test of its nature. A lancet incision 
through the skin into a single one, should it happen so, will de- 
monstrate its melanoid character : the lancet will come out stained 
black, if this be the case. 
In most cases our prognosis, I fear, must be unsatisfactory : the 
size of the tumour, where it is external, its situation, connexion, 
extent, the age of the patient, present state of health and condition, 
are circumstances which must be taken into consideration before 
we hold out hopes of the ultimate result of 
Treatment . — When the internal organs are much affected — 
which will be evidenced by the general emaciation of the frame, 
