456 DISEASE IN WILD MAMMALS AND BIRDS 
the blood exactly as they were ingested like lactose, 
dextrose, etc., are absorbed, but do not enter into the 
economy although they might cause disorders, especially 
forms of arthritis. 
The grain foods are composed largely of carbo- 
hydrates (principally in the form of cellulose and starch) 
small amounts of protein and little or no fat. They have 
a very low nutritive index so that large amounts must be 
consumed to supply adequate calories. This food is 
constantly present, and during the enforced idleness of 
capti\'ity is ahnost continuouly eaten. Despite these facts, 
however, malnutrition is present in 2.2 per cent, of the 
animals on this food. Associated with the plentiful food 
and lack of exercise are overeating and pica. Overfilled 
stomachs occurred thirty-four times. They were limited 
to these mammals and to the seed-eating birds whose 
environmental conditions are practically the same. Pica 
or excessive appetite for abnormal food, is also more fre- 
quent in these groups, but is usually associated with 
badly balanced diets, and thus represents an effort on the 
part of the animal to supply its own deficiency. It is 
present in osteomalacic monkeys and has been reported 
in cattle from regions where osteomalacia is common and 
following crop failures where the rations are restricted. 
In cattle it very often accompanies food poisoning, espe- 
cially that produced by ingestion of peat hay. 
Disturbance of the alimentary tract and its adnexa 
occurs in two forms: (1) Infection which is quite com- 
mon and involves the duodenum, pancreas and liver, and 
(2) toxic. Compared with other diets alimentary dis- 
orders are not frequent among grain feeders, despite 
the ease with which grass foods ferment and the great 
variety of organisms found in them such as moulds 
(aspergillus), Bact. coli, paratyphosus, enteritidis, 
suipestifer, oidium lactis, etc. Few bacteria can 
attack whole protein, cellulose or starch, and the decompo- 
sition products, peptone, glucose, etc., are not available 
