376 
MELANOSIS. 
that of a deep black supplanted it. After clearing away the dis- 
eased portions which I have described, I came upon a fourth mass, 
which had partly been covered by those above. This mass was 
bounded anteriorly by the posterior border of the os hyoides ; su- 
periorly by the transverse process of the atlas ; inferiorly by the 
superior part and upper surface of the trachea, and posteriorly by 
the sterno-maxillaris muscle. This mass was extremely dense and 
impacted ; and by its pressure upon the trachea two effects were 
produced ; first, the cartilages pressed upon were nearly all ab- 
sorbed; and, secondly, the tube of the organ, instead of being round, 
had become a flattened oval. 
Dissection of the brain , nerves, tyc. — Several lobules, from the 
size of a large horse-bean to a small pea, were situated upon the 
facial nerve or portio dura of the seventh pair ; and in one part of 
the nerve, about the middle of the cheek, it was so surrounded and 
enclosed as to be squeezed into a cord-like form*; and a little an- 
terior to this again a lobule lay between the masseter muscle and 
the nerve, which raised the latter from its bed, and tightened it 
considerably : the nerve, however, was perfectly normal through 
its entire course, at least so far as I could examine it with the ne- 
cessary care. 
The par vagum, glosso-pharyngeus, and recurrent laryngeal 
nerves, were all included or embedded in the fourth melanotic mass 
or tumour : the bundles of nervous fibres which constitute the 
trunks were separated by small lobuli, and the nerves were tightly 
stretched ; after which the nervous bundles again united, each to 
its proper trunk, and became lost by passing into the large mass. 
I could not trace their course through the mass, because the dark 
fluid flowed so freely at every incision. The substance of the 
brain was healthy and firm throughout; but 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 very minute ; they 
presented, in fact, what Dr. Carswell would denominate the “ punc- 
tiform” character of melanosis. I next dissected the left eye, and 
found two lobuli, each the size of a large bean, in the situation of 
the lachrymal gland: these lobuli, by pressing upon the globe of 
the eye, had altered the natural form of the crystalline lens; the 
lens resembled a double-fanged molar tooth. All the other struc- 
tures composing the eye were perfectly healthy. 
The organs of respiration, circulation, and digestion, evinced no 
trace of disease. The heart weighed seven pounds avoirdupois. 
Remarks. — The dissection at once explained the cause of cer- 
This nerve is flat naturally in the horse. 
