794 



THE URINE. 



are usually smaller than those of uric acid. Sometimes twin 

 formations of octahedrons are observed. Very rarely it appears 

 in the shape of concentrically striated disks or of dumb-bells. 

 (See Fig. 359.) 



(3) Urate of soda appears in larger quantities under the same 

 conditions as uric acid, with which it is combined, especially in 

 febrile conditions. This salt produces the very common so-called 

 clay- water sediment. It presents fine, amorphous granules of a 

 dark brown color (very rarely colorless, and resembling coagu- 

 lated albumen), in a moss-like arrangement. It adheres easily 

 to foreign bodies (fibers) present in the vessel, and also to mucus 

 and epithelia. When the urine after standing becomes alkaline, 



FIG. 360. 

 URATE or SODA. 



S, ordinary form ; 

 8i, rare form; #2, 

 forms of transition 

 of urate of soda into 

 urate of ammonia. 

 Magnified 300 diam- 

 eters. 



FIG. 361. RARE SEDIMENTS OF ACID 

 URINE. 



If, hippuric acid ; C, cystiue ; L, leucine ; T, 

 tyrosine. Magnified 300 diameters. 



the granules appear in the shape of delicate dumb-bells and in- 

 crease in size, both features being characteristic of urate of am- 

 monia. Uric acid crystals, under the same conditions, break up 

 into clusters of brown globules, which for a while still retain 

 the original lozenge-shape. A rare form of urate of soda is that 

 of needles arranged like sheaves of wheat (Ultzmann). (See 

 Fig. 360.) 



(4) Hippuric acid is of common occurrence in herbivorous 

 animals, especially in the urine of horses ; while in the urine of 



