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 



FIG. 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- 



18 



