22 DISEASE IN WILD MAMMALS AND BIRDS 
said that anesthetics could be used for a thorough exam- 
ination, but this would be undesirable for a seriously sick 
animal and it is, in our experience, none too safe a pro- 
cedure although often perfectly practicable. Animals 
do not like to be molested much as they may seem to enjoy 
attention, and when it is possible it is our practice to 
avoid handling them. 
It might be contended that observations upon diseased 
states in captive animals would not represent natural 
developments, in other words, not that which occurs in 
the wild. Such indeed may be true in regard to the infec- 
tious diseases, but since we are imperfectly informed as 
to the pathology of the wild state, we are obliged to accept 
and use the best substitute at hand. Moreover it seems 
perfectly fair to consider as characteristic for an animal 
or group, the physical and even physiological expressions 
of morbid agencies as we know them, even though the 
animals be at the time under conditions not natural to 
them. It would be perhaps incorrect to say that cirrhosis 
of the liver occurs in .6 per cent, of animals in the mid 
as is the case for our autopsies, since incorrect food and 
infections are potent in its causation ; on the other hand, 
our experience and some few data from naturalists and 
pathologists make it conceivable that tumors occur to this 
number in native states. The incidence of tumors in wild 
rodents is quite 'well know^n. Degenerations and fibroses, 
the result of parasitism, are knowm to exist throughout 
the entire animal kingdom. Further to illustrate how 
pathology is distributed in wild life, Plimmer's 
experience (2) with 500 rats {M. decumanus) might be 
cited. He found the following: Tubercle 3 times, tape 
worm cysts 10, Tryp. lewisi 49, empyema 2, tumor of jaw 
from old injury 1, pleuritis and hydrothorax 1. Bacteria 
w^ere found in 71 rats, 40 times in the lungs, 31 times in 
the spleen ; saccharomyces w^ere found 16 times in the 
lungs. Dr. W. L. Abbott reports to us personally that he 
(2) Proceedings, Zoological Society, London, 1911. 
