REMARKS ON MELANOTIC DEPOSITS. 
By Mr. A. J. Poett, Edinburgh Veterinary College. 
Melanosis is a disease to which few of the veterinary pro- 
fession have thought proper to allude. This is, certainly, rather 
singular, for there cannot be an established practitioner who has 
not met with such cases in the course of his practice : indeed, so 
usual an occurrence is melanosis, that we find very few old grey 
horses that, after death, have not this deposit upon some part of 
their bodies. 
Melanosis attacks all parts of the frame, external and internal; 
but the places where it is usually found are the root of the tail 
or the verge of the anus, and in these places it sometimes accu- 
mulates to an enormous size ; also about the sheath, and the 
neck and front of the chest. 
Internally, it has been seen in the pericardium resembling 
bunches of large black grapes. The liver becomes completely 
^changed in structure by it. The spleen, lungs, and mesenteric 
glands, exhibit it; and, in fact, very few organs are exempt from 
its attack. The most remarkable point connected with mela- 
nosis is, that none but grey horses, and, of the different kinds of 
greys, those of the lightest cast, are its victims. 
Professor Dick, when lecturing on this subject, mentioned that 
he had met with a similar deposit in a bay horse ; which case, 
so far as I know, is solitary. And, l believe, the same gentle- 
man, in a paper on this subject, which was sent to the Lancet a 
few years back, threw out some hints regarding what he thought 
to be the cause why grey horses alone became affected, and 
urged the medical profession to endeavour to clear up the mys- 
tery ; but, as yet, no person has been bold enough to reply. The 
excuse, I am sure, cannot be its lacking interest, for few subjects 
would better repay labour than this. 
The symptoms of this disease are very unsatisfactory ; the fol- 
lowing case will illustrate this : — A mare, the property of 
Fell, Esq., of Sudbury, of a whitish grey colour, and advanced in 
years, was, on the 26th ult., seized with a spontaneous diarrhoea, 
which continued, despite the astringents administered, until the 
29th, when it was checked. My first visit to her was on the 
morning of the 29th, when I found her pulse 100, and full ; 
the respiration very much quickened; the countenance anxious; 
frequent pawing; almost incessant straining; and the small quan- 
tity of urine which was ejected being bloody. 
On the morning of the 30t.h the pulse had fallen to 90, and 
vol. xv. y y 
