URIC ACID. 



63 



found free in urine just discharged. It often constitutes the nucleus 

 of the various forms of urinary calculi. (See "Urinary Concretions," 

 Part II.) 



Fig. 20. 



Fig. 21. 



TJric acid calculus. 



Uric acid calculus, showing internal concentric 

 layers. 



It is demonstrated that the urinary deposit described by Dr. 

 Golding Bird as the urate of ammonia is the urate of soda. (Fig. 



Fig. 22. 



Fig. 23. 



Urate of aoda. 



Urate of soda calculus. 



22.) This salt normally exists in the urine, forming, when abun- 

 dant, the "lateritious sediment," or the "amorphous yellow and 

 impalpable sediment" (Prout) so common in febrile states. It also 

 forms calculi (Fig. 23), and concretions in the joints. Indeed, the 

 urate of ammonia (Fig. 24), very seldom occurs as a urinary de- 

 posit. (Lehmann.) 



