114 NEW YORK ZOOLOGICAL SOCIETY. 
PATHOLOGICAL EFFECTS OF CAPTIVITY ON WILD ANIMALS. 
A certain number of animals die while in captivity of condi- 
tions which might well be classed as old age. During the past 
year I have made a study of what I believe to be the conditions 
leading up to this state, and though as yet my observations are 
brief, I believe it is well to present them in an abstracted form 
at this time. It is well known that in most cases the organs of 
wild animals, even though of considerable age, if free from in- 
tercurrent disease, are practically normal. This is notably so 
inasmuch as we are obliged to resort to these animals to procure 
specimens of many normal tissues, particularly normal liver, 
kidney, and blood-vessels. We practically never find these tis- 
sues in normal condition in the human, even in young children. 
In examining the tissues of animals which have been in captivity 
for a considerable length of time I have been struck with the 
frequency with which we meet changes very like those with 
which we meet so constantly in the human. 
The most common of these changes consists of a fatty degen- 
eration of the parenchymatous tissues of the body, particularly 
of the cells of the liver, and to a slightly lesser degree of the 
kidney. This is accompanied by a parenchymatous degeneration 
of the heart muscle, which in the more pronounced cases is ac- 
companied by fatty degeneration, and sometimes in the more 
sluggish animals by a fatty infiltration. 
The changes in the blood-vessels are those of arterio-sclerosis 
of variable degree. In my observations I have rarely found this 
to extend to actual atheroma, but a fatty degeneration of the walls 
seems to represent more frequently the most extreme stage. 
Arterio-sclerosis is usually most manifested in the arterioles by 
a proliferation of the adventitia and of the perivascular connect- 
ive tissue. This is probably associated with more or less marked 
interference with the functions of the vasa vasorum. It is very 
likely that these alterations in the blood-vessels are among the 
earliest changes, and that they are often the primary lesions 
which induce the latter parenchymatous alterations. 
The cause of these tissue changes are probably multiple. In 
my opinion the most frequent and common etiological factors are 
two in number: over-nourishment; insufficient exercise. These 
factors go hand in hand, and one is probably always associated 
with the other. We therefore find these changes taking place 
to a most marked degree and earliest in animals with which the 
amount of food is not absolutely under control, and in those ani- 
