354 DISEASE IN WILD MAMMALS AND BIRDS 
Analysis of the bones shows a loss of calcium and an 
excess of sulphur and magnesium. The loss of the first 
is chiefly via the intestinal discharges but also via the 
urine. The metabolism of one monkey showed a high 
calcium and phosphorus loss with moderate retention of 
sulphur and magnesium. 
Because of the importance of osteomalacia and 
rickets in cebus monkeys and certain other animals, Dr. 
E. P. Corson- White has been investigating its etiology. 
I shall refer briefly to her results as they aifect our pres- 
ent subject but shall leave for discussion in the chapter 
on diet, which she has written, the broader question of 
food and systemic disease. 
It must be understood that the instances included in 
this general discussion of degenerative osseous disease 
are cases of definite character and development. There 
may have been, in addition to the numbers cited in the 
list on page 357, many more animals at autopsy with 
early or unrecognized constructive or destructive abnor- 
malities, and we are thoroughly familiar with the 
imperfect skeletal development of specimens, inbred or 
reared in captivity or even those adult when caught yet 
under Park conditions for many years. In these latter 
groups the changes vary from incomplete construction 
(an example of atrophy was quoted on page 24) to actual 
degeneration as in osteomalacia. Inbreeding seems to be 
a potent factor in many cases, a well known fact in human 
and veterinary medicine. The importance of inactivity 
in the causation of degenerative bone disease, the unused 
muscles giving the bones nothing to do, is certainly admit- 
ted but it is immeasurable. It is probably not great in a 
cage of mixed varieties of monkeys. The effect of the 
absence of sunlight in osseous degeneration is no factor 
in our material. The exhibition house is well lighted and 
many animals are out of doors all year around. 
The ductless glands have repeatedly been accused of 
responsibility for these disorders. In our seventy-nine 
