744 



PHYSIOLOGICAL CHEMISTRY. 



The following crystals occur only in abnormal urines : 

 Leucine, or amino-caproic acid, C 6 H n (XH 2 )O 2 , and Tyrosine, 

 C 9 H U NO 3 , are but rarely met with in urinary deposits. Leucine is 

 found either as rounded lumps, showing but little crystalline structure, 



FIG. 81. 



Tyrosine crystals. (Charles.) 



or as spherical masses, exhibiting fine radial striation. Tyrosine 

 appears generally in fine, long, silky needles, forming bundles or 

 rosettes. 



Cystine occurs occasionally as a grayish, crystalline deposit, form- 



FIG. 82. 



Crystals of cystine spontaneously voided with urine. (Roberts.) 



ing transparent six-sided plates ; it also occurs in calculi. The latter 

 may be recognized by the chemical properties mentioned below, or by 

 dissolving a little in hydrochloric acid and neutralizing with ammonia, 

 when cystine is reprecipitated and shows the characteristic six-sided 

 plates under the microscope. 



