THE 
YETERIN 
VOL. XXXV. 
No. 409. 
JANUARY, 1862 . 
Fourth Series. 
No. 85. 
Communications and Cases. 
ON MELANOSIS. 
By Assist.-Professor Yarnell, Royal Veterinary College. 
Melanotic deposits are by no means rare in the horse. 
There is scarcely an organ in the body of this animal in 
which I have not seen this, pigment deposited in its tissues; 
and although many cases are recorded in the pages of the 
Veterinarian , and other veterinary works, yet I am not aware 
that the pathology of this disease has been freely discussed, 
or its varieties investigated with a view to a systematic 
classification ; and until this is done, we shall always be in 
danger of confounding simple melanosis, which is by far the 
most common in the horse, with that of a malignant 
character. 
The former, unless the deposit is excessive, and an im¬ 
portant organ involved, is comparatively harmless, while the 
latter is highly injurious. A clear insight into the histology 
of such abnormities requires the aid of the microscope for 
their elucidation, and he who undertakes it will be amply 
repaid for his trouble by the benefit he confers on the mem¬ 
bers of the profession. Cases from which specimens can be 
obtained for examination are comparatively numerous, there¬ 
fore on that score we have no excuse. 
For the assistance of those who may be desirous of contri¬ 
buting to veterinary pathology the results of their investigation 
of this disease, I have thought the following cases worth re¬ 
cording, since with others already published they may serve 
as data on which their conclusions may be based. 
The first was forwarded to me by Mr. H. W. Hooper, 
XXXV. 1 
2-\£ G& 
