338 
MELANOSIS AND OSSIFICATION. 
little to do, as I believe it is seldom seen in his patients: the foU 
lowing observations will therefore be confined to the consideration 
of the first or true form of melanosis, which comes under his 
notice a great deal oftener than under that of the practitioner of 
human medicine. Four varieties of this form have been denomi? 
nated : — 
1st. Punctiform melanosis , in which the black colouring matter 
appears in the shape of minute points or dots, either grouped in a 
small space, or scattered irregularly over a considerable extent of 
surface. 
This variety of melanosis is described by Mr. W. Haycock, V.S., 
of Huddersfield. The subject was an old grey mare, who had a mela- 
notic tumour placed over the articulation of the inferior maxilla, and 
respecting whom Mr. H. writes, in The Veterinarian for 1847, 
thus : “At the junction of the cerebellum with the medulla was a 
quantity of areolar tissue, which contained a great number of minute 
red and black specks; these black specks were very numerous, but 
were very minute: they presented, in fact, what Dr. Carswell would 
denominate the punchiform character of melanosis.” 
2d. Tuberiform melanosis , more common than the preceding 
form, where the tumour varies from the size of a millet-seed to 
the bulk of a child’s head, or even of more considerable dimensions. 
It is in the loose cellular and adipose tissues that these melanotic 
tumours are disposed to attain great magnitude. Their large size 
seems to depend upon the agglomeration of numerous small tu- 
mours ; they are met with encysted and without a cyst. This va- 
riety is not confined to any tissue, but may be seen in the cellular 
and adipose tissues or parts abounding in them, and on the surface 
of the peritoneum and pleura, as the post-mortem appearances of 
my own case of the Horsford mare will clearly demonstrate. 
3d. Stratiform melanosis , occurring only in the surface of serous 
membranes. In the first stage the part is merely stained with the 
matter; in the second a distinct layer is deposited on the surface, of 
the consistence of jelly, and is enclosed either in cellular tissue or 
in a transparent membrane of new formation : it is not removed by 
passing the finger or scalpel over it. In some cases it forms a 
black coating, in appearance like what is produced by Indian ink. 
Mr. J. D. Harrison, of Southport, in The VETERINARIAN for 
1841, furnishes a good illustration of this variety of melanosis co- 
existing with the tuberiform. After describing the appearance of 
the latter, he says, “on the pleura and peritoneum the disposition 
of the matter was somewhat different ; it was effused on the surface 
of these membranes, notin round masses , but in streaks and patches. 
There seemed to have taken place on their surfaces a formation of 
cellular tissue, into which the black matter appeared to have been 
