ZOOLOGICAL DISTRIBUTION OF DISEASE. 257 
thin sections under the microscope, the affected tissues 
are found impregnated with feathery tufts of crystals, 
which respond to the ordinary tests for guanin. 
From the hog we may turn to parrots, which frequently 
present in their subcutaneous tissues, cartilages, skin, 
muscles, and intestines, nodules, which, in their naked- 
eye characters, are indistinguishable from gouty nodules 
F1G. 124.—Microscopic section of the articular cartilage of a 
pig’s knee-joint affected with guanin gout. (After Men- 
delson.) 
as seen in man. Indeed such deposits have been de- 
scribed as gout, not only in parrots, but in fowls, falcons, 
ostriches, &c. In the drawing (fig. 125), the foot of a 
parrot is represented with characteristic nodules, and 
when cut into, the centre of such nodules is occupied by 
a white mortary-looking substance in every way resem- 
bling that known as chalk (urate of soda) in human 
gout. The analogy goes beyond mere naked-eye cha- 
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