422 DISEASE IN WILD MAMMALS AND BIRDS 
fat or protein, independent of any actual infection. The 
symptoms arising from bacterial decomposition of foods 
depend largely on the organism concerned and vary from 
a mild intoxication to a severe toxemia. 
Relation of Dietary Groups to Autopsy Diagnoses. 
Analysis of the autopsies on file from sole point of 
view of dietary habits of the animals gives rather inter- 
esting groupings of disease states, which apparently and, 
in some cases definitely, emphasize the relationship 
between food, metabolism and disease. (Table 19.) 
From this table a few facts stand out prominently. 
It is definitely sho\\Ti that both birds and mammals on a 
diet of mixed animal and plant tissue show a low per- 
centage of disease in the gastrointestinal tube, liver, 
pancreas and kidney. The mammals on this diet give the 
highest figures for anemias and degenerative osseous 
conditions. Birds on this diet show very little osteo- 
malacia, but a fair amount of anemia. Possibly this may 
be accounted for by the fact that all of them pick gravel 
and may be able from tliis to supply some of the inor- 
ganic deficiency. Carnivorous birds and mammals, on the 
other hand, show an exceedingly large assortment of 
gastrointestinal disorders, diseases of the accessory 
glands of digestion, and of the kidneys. Disorders of the 
thyroid gland are almost entirely confined to carnivorous 
mammals — 7.5 per cent., compared to 0.25 per cent, in all 
other orders. Gout, while common among birds, was not 
present in any mammalian autopsy, while arthritis in 
mammals reached its highest record among grass- and 
grain-eating herbivora. The percentage of rickets was 
highest in the young carnivores (2.6 carnivores as against 
.4 per cent, in all other mammals), and was very rare 
among all birds. 
The succulent vegetable diet was lowest in its relation 
to degenerative visceral disorders and highest in acute 
gastritis ; the latter fact was probably due to the f ermen- 
