4 88 EXCRETION 



terial action have been demonstrated in the urine in certain diseases. 

 Red blood-corpuscles and leucocytes (pus corpuscles, white blood- 

 corpuscles, mucous corpuscles) are the chief organized deposits; but 

 spermatozoa may occasionally be found, as well as pathogenic bacteria 

 e.g., the typhoid bacillus; and in disease of the kidney casts of the renal 

 tubules are not uncommon. These tube-casts may be composed chiefly 

 of red blood -corpuscles, or of leucocytes, or of the epithelium of the 

 tubules, sometimes fattily degenerated, or of . structureless protein, 

 or of amyloid substance. Abnormal crystalline substances, stich as 

 the amino-acids, leucin (Fig. 186), tyrosin (Fig. 187), and cystin 

 (Fig. 1 80), may be on rare occasions found in urinary sediments; but 

 generally the unorganized deposits of pathological urine consist of 

 bodies actually contained in, or obtainable from, the normal secretion, 

 but present in excess, either absolutely, or relatively to the solvent 

 power of the urine. Cystin is of interest because of its relations to the 

 sulphur of the protein molecule (p. 360). It is not found in the normal 

 organism. It very occasionally forms calculi in the bladder. There 

 arc individuals who constantly pass as much as one-fourth of all the 

 sulphur in the form of cystin, without any other symptoms. 



Various amino-acids are present in solution in the urine in many 

 pathological conditions. Of these the least soluble are leucin and 

 tyrosin, and this is the reason why they are most easily detected. A 

 general reaction for ammo-acids is their precipitation as sparingly 

 soluble compounds (|3-naphthalinsulphones) by /3-naphthalinsulpho- 

 cWpride in the presence of an alkali (sodium hydroxide). In acute 

 yellow atrophy of the liver leucin and tyrosin have been found in large 

 amounts in the liver itself, as well as in the urine. In phosphorus 

 poisoning these amino-acids, as well as glycocoll, have been detected in 

 the urine, and there is no doubt that other amino-acids, arising from 

 the decomposition of proteins, are also present in such conditions. 



Sugar. In diabetes mellitus, although the quantity of urine is usually 

 much increased, its specific gravity is above the normal; and this is due 

 chiefly to the presence of sugar (dextrose), which generally amounts 

 to i to 5 per cent., but may in extreme cases reach 10 or even 15 per 

 cent., more than half a kilogramme being sometimes given off in twenty- 

 four hours. 



The name of the tests for dextrose is legion. They are mostly 

 founded on its reducing action in alkaline solution. Hydrated oxide of 

 bismuth (Boettcher), salts of gold, platinum and silver, indigo (Mulder), 

 and a host of other substances, are reducsd by dextrose, and may 

 be used to show its presence. The reduction of cupric salts (Trommer), 



Fig. 186. Leucin Crystals. Fig. 187. Tyrosin Crystals. 



fermentation by yeast, and the formation of crystals of phenyl-gluco- 

 sazone are the best established tests. (See Practical Exercises, p. 517.) 

 Proteins. Serum-albumin and serum-globulin are the proteins most 

 commonly found in pathological urine. Both are coagulated by heating 

 the urine, slightly acidulated if it is not already acid, or' by the addition 



