122 DISEASE IN WILD MAMMALS AND BIRDS 
TUMOES. 
The neoplastic enlargements are represented by a 
lymphosarcoma of the mediastinum in a Dorcas Goat; 
there were secondary growths in the liver, the kidney and 
several isolated lymph glands. Secondary growths from 
original tumors not in the lymphatic system are curiously 
rare, certainly much less frequent than is found in the 
human being. In ninety-two tumors which are known to 
give metastases, only three involved the lymphatic glands 
and only one of these could be considered as involving 
nodes not in the ordinary drainage pathway. 
The Spleen. 
The spleen is an organ whose exact position in the 
scheme of things remains mystifying through the whole 
series of animals. Its functions have been arrived at 
largely by exclusion, somewhat by conjecture and specu- 
lation, while the acceptably proven duties are indeed few. 
Although this is not the place to enter into a discussion of 
all the points at issue concerning the anatomy and func- 
tion of the organ, a few facts might be mentioned of 
comparative and perhaps pathological value. While the 
spleen has been looked upon always as the origin of blood 
cells in the embryo, cases in man are on record where no 
spleen was discovered, a condition suggesting that its 
absence is not incompatible with life ; that such is the case 
is obvious for experimental or therapeutic removal of 
the organ is well known. 
It was suggested by Virchow that at times the spleen 
assumes the duty of the bone marrow and the swelling of 
the viscus in certain anemias seems to support this state- 
ment. However, there is no physical relationship between 
the size of the animal and that of the spleen, nor between 
the available quantity of bone marrow, the obvious rich- 
ness of circulating blood and amount of lymphatic tissue. 
This is well shown in the water mammals which have a 
great deal of blood in vessels and viscera yet their spleen 
