116 NEW YORK ZOOLOGIGAE SOCIETY: 
of Drs. Miller and Blair I have also been able to see and study a 
few clinical cases. 
“Cage paralysis” is generally recognized by animal men as a 
distinct disease. The few veterinarians who have become sufficient- 
ly versed in the diseases of wild animals are also generally inclined 
to look upon it as an entity, though they make a distinct differen- 
tiation from certain rheumatic symptoms which uninstructed men 
would be very apt to call and to mistake for actual spinal disease. 
Occurrence.—The disease occurs almost exclusively among wild 
animals, though a few cases are also probably seen among certain 
domesticated ones. It is found most commonly among the higher 
mammals, principally among bears and primates. Of the pri- 
mates, in which the disease is by far the most frequent, the lower 
types, such as the lemurs, are not often attacked, though baboons, 
macaques and other examples of the lower monkeys are affected. 
In general, we might say that it occurs most frequently in those 
animals which habitually or commonly assume the upright gait. 
Its occurrence is not limited to, or more usual in, animals from 
any one part of the world. I have found no instances of its being 
found among those in the wild, and Mr. Hornaday, whose nu- 
merous observations of wild animals in their natural habitat are 
well known, tells me that he has never seen it in a wild animal, 
either free or at the time of its capture. However, he adds the 
very significant statement that an animal, even in the early stages 
of the disease, is so seriously handicapped that it would in all 
probability soon die of starvation or fall prey to the carnivorous 
animals which are generally found in the same habitat; hence, 
though it is rather improbable that it occurs in nature, it is still a 
question which will probably never be really settled. 
Sex.—tIn so far as our observation goes, the disease occurs 
equally in both sexes. 
Age.—The disease may appear in either old or young animals, 
and there seems to be no relation between age and occurrence. 
It does apparently affect more frequently those animals which 
have been in captivity a long time, and hence it is, perhaps, most 
frequent in old animals. Bearing on this fact, we must remember 
that under the usual conditions the life of many primates in cap- 
tivity is perhaps fully as long as in the open. 
Etiology.—Absolutely nothing definite is known of the etiology 
of the disease. By some it is thought that it is caused by exposure, 
but, as in the cases at the New York Zoological Park, this is ex- 
cluded by an automatically adjusted temperature and by the 
greatest possible care. Some think that it develops as a result 
of the unnatural character of the floor on which the animals are 
