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CHAPTER VI. 



THE PHYSIOLOGY OF URIC ACID AND 

 OTHER URINARY DEPOSITS. 



Uric Acid : Derivation from food-stuffs ; Derivation from the 

 tissues ; The purin bodies ; Gout Calcium oxalate Cystin 

 General laws of calculus formation. 



THE substances which may form a crystalline 

 deposit in the urine are many, but we shall 

 here refer only to three, namely, uric acid and the 

 urates, oxalate of calcium, and cystin. We shall 

 first consider what light has been thrown upon the 

 origin of these substances in the animal body, and 

 then inquire what are the factors that lead to their 

 precipitation and aggregation in the form of calculi. 



URIC ACID AND THE URATES. 

 For many years totally erroneous views were held 

 by physiologists with regard to the origin of these 

 substances. It has been customary to argue the 

 physiology of the mammal from that of the bird, 

 with disastrous results. Removal, or rather isolation, 

 of the liver in geese was shown by Minkowski to 

 diminish the output of uric acid, whilst ammonium 

 salts and lactic acid were increased in the urine. 

 Hence it was concluded that uric acid was formed 

 in the liver from ammonium salts and lactic acid; 

 and for birds and reptiles this is true. In mammals, 

 the metabolism is totally different. The end product 



