CONSTITUTIONAL DISEASES 411 
In so far as etiology of this disease is concerned in 
domestic stock, too rich food, especially in protein, and 
restriction of activity seem to be credited with the 
greatest influence. These factors, while doubtless of 
importance for birds as they are believed to be for man, 
do not seem to fill aU the requirements since all our 
specimens are confined and, because of their lack of exer- 
cise, possibly receive too much food. Judging by our 
observations and by publications from other gardens, 
carnivorous birds are not conspicuous for the incidence 
of gout whereas grain- seed- and fish-eaters suffer more 
often. This suggests that these varieties cannot dispose 
of dietary protein which might be excessive for their 
metabolism while in captivity, whereas carnivorous 
species have a digestive and chemical reserve to take care 
of excess protein. Some such accommodative power must 
exist in human beings since not every large meat-eater 
develops gout. Heredity, often blamed for the human 
disease cannot help us with these birds. Examination of 
the diet list at the Garden does not reveal a great per- 
centage of concentrated protein in the feed of the grain- 
and seed-eaters. The disease occurs too seldom to 
disturb the accepted dietary for its possible elimination. 
Studies now going on may indicate appropriate changes 
in the dietaries that might be responsible. 
Arthritic gout appears usually in the pedal joints 
but may be found in the wings. Irregular, sometimes 
very deforming swellings appear which must be tender 
judging by the quietness of the bird and by its behavior 
if the joints be touched. Most often the swelling seems 
greater upon the flexor (palmar) surfaces of the toes or 
in the end of the tarsal articulation. Aside from these 
few observations there is nothing peculiar about the at- 
tack or the specimen during its sickness. Chronicity seems 
to be the rule and little emaciation may be found. 
Appetite is normal or excessive, provided the food can 
be reached. 
