230 Dr. Wollaston on Cystic Oxide , &c. 
hawk, fed upon flesh alone, the quantity of matter voided in 
a solid state bears but a small proportion to the residuum of 
uric acid, that is left by the urine when dry. And in the 
gannet feeding solely on fish, I have observed the evacuations 
in some instances to be mere urine, for it contained no solid 
matter, excepting the uric acid. 
It seems consequently, deserving of inquiry, what changes 
might be produced in the urine of any one animal, by such 
alterations of diet, as its constitution would permit; for as far 
as any inference can be drawn from these varieties, which 
naturally occur, it would appear, that persons subject to cal- 
culi, consisting of uric acid, as well as gouty persons, in whom 
there is always a redundance of the same matter, have much 
reason to prefer vegetable diet, but that the preference usually 
given to fish above other kinds of animal food, is probably 
erroneous. 
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