350 PHYSIOLOGICAL CHEMISTRY. 



with the other, i. e., whenever leucine is detected it is more than 

 probable that tyrosine accompanies it. They have been found path- 

 ologically in the urine in acute yellow atrophy of the liver, in acute 

 phosphorus poisoning, in cirrhosis of the liver, in severe cases of 

 typhoid fever and smallpox, and in leukaemia. In urinary sedi- 

 ments leucine ordinarily crystallizes 

 FIG. 104. ^^^^ m characteristic spherical masses 



which show both radial and concen- 

 tric striations and are highly refrac- 

 tive (Fig. 104, p. 350). Some in- 

 vestigators, claim that these crystals 

 which are ordinarily called leucine 

 are in reality, generally urates. For 

 the crystalline form of pure leucine 

 9 obtained as a decomposition product 



CRYSTALS ( F ^RE LEUCINE. Q protein see Fig> 2 ^ p> fa Tyro- 



sine crystallizes in urinary sediments 



in the well-known sheaf or tuft formation (Fig. 23, p. 72). For 

 other tests on leucine and tyrosine see pages 83 and 84. 



Haematoidin and Bilirubin. There are divergent opinions re- 

 garding the occurrence of these bodies in urinary sediment. Each 

 of them crystallizes in the form of tufts of small needles or in the 

 form of small plates which are ordinarily yellowish-red in color 

 (Fig. 41, p. 153). Because of the fact that the crystalline form of 

 the two substances is identical many investigators claim them to be 

 one and the same body. Other investigators claim, that while the 

 crystalline form is the same in each case, that there are certain 

 chemical differences which may be brought out very strikingly by 

 properly testing. For instance, it has been claimed that haematoidin 

 may be differentiated from bilirubin through the fact that it gives 

 a momentary color reaction (blue) when nitric acid is brought in 

 contact with it, and further, that it is not dissolved on treatment 

 with ether or potassium hydroxide. Pathologically, typical crystals 

 of haematoidin or bilirubin have been found in the urinary sediment 

 in jaundice, acute yellow atrophy of the liver, carcinoma of the liver, 

 cirrhosis of the liver, and in phosphorus poisoning, typhoid fever 

 and scarlatina. 



Magnesium Phosphate. Magnesium phosphate crystals occur 

 rather infrequently in the sediment of urine which is neutral, alka- 

 line or feebly acid in reaction. It ordinarily crystallizes in elon- 

 gated, highly refractive, rhombic plates which are soluble in acetic 

 acid. 



