136. OBSERVATIONS ON THE ANATOMY OF 
parts of these organs to sink when immersed in water; 
they abounded on the pericardium, on the large arterial 
trunks, on both sides of the diaphragm, on the coats of the 
intestinal canal, on the surface and through the whole sub- 
stance of the liver ; the pancreas and the spleen were masses 
of tubercles ; they were spread over the peritoneum, they 
extended through the substance of the kidneys to the pa- 
rietes of the pelves; and the bronchial and mesenteric glands 
were very much enlarged and hardened, exhibiting the 
same firm cheesy consistence as the whole of the tubercles. 
No hydatids were found in any of these organs ; but I have 
found on the omentum of the domestic rabbit large speci- 
mens of the hydatis pisjformis Lam<, while the liver of the 
same animal was entirely traversed with small, hard tuber- 
cles. 
The cartilaginous rings surrounding the trachea, and its 
principal branches in the Paca, cover four-fifths of the cir- 
cumference of these tubes, as in the Guinea-pig. The 
lungs are divided into three lobes on each side of the chest, 
and the heart lies in a longitudinal position on the mesial 
line. Each lung was similarly divided, by two transverse 
fissures, into three lobes; the smallest of which tapered 
upwards to the imperfect clavicle, the lowest was consider- 
ably the largest, and tlie middle lobe was bounded, above 
and below, by two flat and parallel surfaces. A very small 
additional lobe, about an inch in length, and much divided, 
was placed at the lower and back part of the right lung, 
making four lobes on the right side, as in most other qua- 
drupeds. The heart was comparatively small, soft, and 
pale colovu^ed. The right cavities were more thin and flac- 
cid tlian is commonly observed ; there was no opening at 
the place of the foramen ovale ; the opening and sinus of 
the coronary veins were unusually ^^'ide, and terminated 
on the right side of tlie right auricle, immediately above 
