PATHOLOGICAL ANATOMY. 
139 
abdomen. MM. Trousseau and Leblanc found, on a horse’s kid- 
ney, a fibrous cyst of the bulk of a fist, which contained about eight 
ounces of a black fluid. It is formed of the different elements of 
the blood, and particularly of the colouring matter of that fluid ; and 
there is scarcely a tissue in which it has not been found in one or 
another of the forms just described. It has been found in the sub- 
cutaneous cellular tissue, in the submucous tissue, and on the in- 
ternal surface of the intestines. It has been deposited between the 
muscular and peritoneal coats of the intestine — between the pleuro- 
pulmonalis and the substance of the lung — between the pericardium 
and the heart ; but most generally in the cellular tissue interposed 
between the muscles, or between the fasciculi of the same muscle. 
M. Andral saw, in a horse affected with hydrocele, the portion of 
serous membrane that covered the tunica albuginea of one of the 
testicles presenting a round spot as black as ebony, about the size 
of a five-franc piece ; and not far from this large spot were three or 
four smaller ones of a less regular form, and rather slate-coloured 
than black. 
Melanosis has been seen in the different tissues composing the 
parietes of the arteries. It has not yet been found in the parietes 
of the veins. The osseous tissue has been little affected by it, 
but it has not often been seen in either the fibrous or cartilaginous 
tissues. In the muscles it has rarely been found to involve the 
muscular fibres themselves, but only the cellular tissue uniting 
them ; he, however, quotes a case from Trousseau and Leblanc, in 
which the proper tissue of the muscles had been infiltrated. A 
white horse had a melanic tumour on the perineum. Some of the 
muscular masses at the posterior part of the thigh were found to 
be much paler than in the natural state. Inferiorly they became 
insensibly confounded with the rest of the muscles proceeding 
from the ischium to the tibia. On the contrary, advancing up- 
wards, they grew paler and paler — the cellular tissues uniting their 
fibres became of a greyish colour, and, at last, the muscular fibres 
themselves, which had become harder and more coherent, and 
grating under the knife, assumed a tinge of the deepest black, and 
in this state proceeded to their attachment at the ischium, still, 
however, preserving their fibrous appearance. Their tissue was 
dry, and exceedingly difficult to break down : the tendons and 
aponeuroses had alone escaped the melanic infiltration, and the 
ischium itself was tinged black to a great depth, and was remark- 
ably friable. 
Of the muscles of organic life, the heart is the only one that 
has been found in a state of melanosis, and there is only one case 
of this on record. It is often found in the lungs, but never in 
