PIGH THY ANNUAL REPORT: LG 
confined, but this does not seem to be well founded, since it ap- 
pears alike in animals confined in the ordinary board-floor cages 
of the travelling menageries, in metal cages, the floor of which 
is covered by some soft substance, and in those which have the 
ground as a floor. The cleanliness of quarters does not seem to 
affect the etiological factors, for the disease apparently occurs 
as frequently in the scrupulously kept enclosures of the New York 
Zoological Park as in the often foul quarters of the animal deal- 
ers. Confinement in smaller cages apparently offers some predis- 
position to the disease, since we have observed fewer cases occur- 
ring in the larger, more airy, and best-lighted cages; most of 
the cases developing in the smaller and darker side compartments. 
Food has apparently no effect on the disease. The mental effects 
of restraint apparently do not act as a causative factor, for as a 
rule the disease occurs in those animals which take very kindly 
to cage life, and it does not appear more frequently in those ani- 
mals which are most affected by confinement and restraint. The 
mentality of the animals bears no apparent relationship to the 
onset of the disease. 
A few cases are found which have followed traumatism, but 
the instances have been so few as to almost lead one to the con- 
clusion that they have always been but coincidences and that in- 
jury in reality had nothing to do with the onset. The character 
of the food has apparently nothing to do with the causation of 
the disease, for at the New York Zoological Park the food is 
very thoroughly inspected, and the amount and character is care- 
fully controlled. Nevertheless it is generally admitted that the 
disease occurs mostly in animals which have been in captivity for 
a considerable length of time, and animal men, who as a rule 
are keen observers, are convinced that the cause of the disease is 
in some way connected with the effects of captivity. 
Onset.—The first symptom generally noticed is a stiffness of 
the lower extremities, manifested in that the animal is not as 
quick and agile as usual and soon ceases to attempt the more dif- 
ficult feats which the monkeys in particular are so fond of doing. 
This stiffness is generally more evident on one side than the 
other, and the actions of the animal resemble those of one suffer- 
ing with rheumatism. They often continue to feed and look well, 
but once the initial stiffness has appeared, the disease almost al- 
ways progresses with at least observable rapidity, finally affecting 
both of the rear extremities. During this period the animal is 
apparently free from pain and, if accustomed to handling, does 
not resent it at this time. It is not evident that pain is produced 
by the manipulation of the partially paralyzed extremities. 
