620 DISEASE IN WILD MAMMALS AND BIRDS 
locus resistenticB minoris. The intestinal tract is the 
most common organ concerned, but the illustrations to 
follow will give variety. Thus, the mature examples of 
cesophagostoma in young rhesuses just referred to above 
burrowed into the gut wall and led to both local and gen- 
eral peritonitis. In one of our ''spiroptera" parrots the 
worm had passed through the proventricular wall and a 
chronic fibrosis resulted around it. At the autopsy on a 
Rhesus Macaque Doctor Fox found a localized abscess 
adjacent to the gut wall, and in it a whipworm was 
imbedded. Passing from these examples of intestinal 
worms, I can mention the loss of a valuable Philippine 
Spotted Deer {Cervus alfredi) as the result of secondary 
infection of a cysticercus cyst of the lesser omentum 
which led to a nearby peritonitis. Lung infections 
are not uncommon. Murray (8) records that forty-four 
out of eighty-five young rhesus monkeys dying from pneu- 
monia showed an acarian, and he ascribed the pulmonary 
irritation to certain crystals in the excreta of the mite. I 
have studied a case of bronchopneumonia in a prairie dog 
where great numbers of an arachnid were present. The 
reports of the London Zoological Society are replete with 
notes of round worm pneumonias of reptiles. These pul- 
monary cases must result from decreasing of tissue 
resistance by the presence of the worms, and are easy to 
understand, much more so than the intestinal infections 
when one recalls how sensitive lung tissue is to foreign 
bodies, and that there seems to be no indication that this 
tissue becomes accustomed to infestation such as may be 
argued for the gut. All these citations must convince us 
that parasites are most important predisposing agents 
to infection, and that this is one of the most sinister 
phases of animal parasitism. 
5. DESTRUCTioisr OF Tissue. — This heading does not 
refer to the comparatively trivial effects that accompany 
the more acute inflammations secondary to parasites, 
(8) Proc. Zool. Soc. London, 1919, p. 15. 
