SECTION XVI 
NEOPLASMS 
The occurrence of true neoplasms in domesticated 
animals has always been well kno\\m and thoroughly 
studied while for beasts in the wild the data has been 
fragmentary. That tumors exist in natural environment 
has been accepted upon the testimony of hunters but 
there is an impression, and nothing more, of their 
extreme scarcity probably because only younger vig- 
orous animals come to the attention of the sportsman 
or collector. This matter will of course not be 
settled until some natural historian with a Imowledge 
of pathology, makes a survey of a large number of speci- 
mens taken during a collecting expedition. Observations 
in menageries are valuable to the extent that they show 
what tumors may occur, the orders most commonly 
aifected and the incidence under captive conditions. It 
is unfortunate that too seldom do we know the history of 
our specimens in regard to the age, manner of capture 
or breeding, data which if at our disposal would permit 
of a very fair idea of the probable incidence in the wild 
and of the effect of captivity. Some observations in this 
direction are however possible by using the figures of 
known captivity and breeding. 
The facts gleaned from a study of neoplasms under 
captive conditions may be of interest to the experimental 
pathologist, especially when considering the relation of 
the origin from the embryological layers. I have tabu- 
lated this with great care, using Jordan's (1) table for 
the source of the various tissues, and further have studied 
the destination of metastatic emboli in terms of 
the blastoderm. 
The following observations are based entirely upon 
our own data for while it might be valuable to include the 
cases in the literature their descriptions are often so 
(1) Textbook of Histology, 1920. 
462 
