106 DISEASE IN WILD MAMMALS AND BIRDS 
The histology of the organs may be described together. The infil- 
trate described is a densely packed mass of large cells with large, well 
staining nuclei and a very narrow rim of protoplasm. It is not limited 
by any definite wall or septa. It has no interstitial tissue. There is no 
blood supply in the densest masses but the walls of the blood vessels 
remain intact wherever the mass surrounds them. In the lungs it has 
involved all structures indiscriminately, and has destroyed practically 
all of the respiratory surface. It seems to follow by preference the 
peribronchial space. A few glands may be seen in the centre of this 
mass, but they are rapidly undergoing degeneration. In the liver the 
infiltrate is chiefly beneath the capsule extending inward but a very 
short distance. There are no large masses as in other organs but small 
infiltrates are seen at the portal areas. The spleen shows a diffuse 
excess of pulp cells and many of the cells above described, the difference 
being only in the size of the nucleus which is smaller in the pulp cells. 
There are very small round cells relatively. Follicles are absent, connec- 
tive tissue not altered. Note states follicles prominent; this is due to 
nodal hyperplasia of the large mononuclears above described. The 
parenchyma in the kidney is anemic, the epithelium is slightly pigmented 
but this is probably not abnormal. Between the tubules especially of 
the outer layer of the medulla and medullary ray but also in the cortex 
and around the glomeruli are diffuse, irregular, infiltrating masses of 
the cells as described above. In some places in the kidney hyaline casts 
are being formed probably due to the degeneration of the epithelium 
by pressure. There ai'e a few distentions of the tubules. The capsular 
space is free. In the neighborhood of the collections the capsules are 
a trifle thicker than normal. Lymph nodes, similar to spleen in that 
most of the bodies are thoroughly overrun with the large mononuclears. 
The sinuses, both marginal and internal, are practically obliterated by 
these cells. In the blood vessels of the lungs and liver there are many 
large mononuclears, perhaps not as large a number as might be seen 
in leucemia, but decidedly in excess of normal. 
Common Marmoset {Callithrix jacchus). 6 Adult. Had cage 
paralysis for two months before death and declined gradually from 
that time. 
DiAGXosis. — Bronchopneumonia. Myeloid hyp.erplasia of bone mar- 
row. Myeloma in pancreas. Fatty degeneration of liver. Constipation. 
Nematodes in cecum. Animal is thin, skin bare in spots. Both lungs are 
pale pink with large areas of deep red consolidation. Heart is dilated, 
increased in size with firm, red-brown muscle. Liver is firm, red-brown, 
with smooth surface and sharp edges. Section surface is glistening, 
smooth and moist. Lobular outlines are clear by reason of pale lines. 
The gall-bladder is normal in size and contains fluid pale green bile; 
duct patulous. Spleen is normal in size, smooth capsule, soft, purple 
pulp, follicles small and faint, trabeculae fairly prominent. Kidneys 
normal in size and shape. Capsule smooth. Section surface smooth and 
brown and firm. The glistening section surface has a narrow cortex, 
