URINE. 285 



acid is found to be increased in amount in diabetes mellitus, in or- 

 ganic diseases of the liver and in various other conditions which 

 are accompanied by a derangement of the oxidation mechanism. 

 An abnormal increase of oxalic acid is termed oxaluria. ' A consid- 

 erable increase in the content of oxalic acid may be noted unaccom- 

 panied by any other apparent symptom. Calcium oxalate crystal- 

 lizes in at least two distinct forms, dumb-bells and octahedra (Fig. 

 99, page 345). 



EXPERIMENTS. 



Preparation of Calcium Oxalate. First Method. Place 200- 

 250 c.c. of urine in a beaker, add 5 c.c. of a saturated solution of 

 calcium chloride, make the urine slightly acid with acetic acid and 

 stand the beaker aside in a cool place for 24 hours. Examine the 

 sediment under the microscope and compare the crystalline forms 

 with those shown in Fig. 99, p. 345. 



Second Method. Proceed as above, replacing the acetic acid by 

 an excess of ammonium hydroxide and filtering off the precipitate 

 of phosphates. 



NEUTRAL SULPHUR COMPOUNDS. 



Under this head may be classed such bodies as cystine (see p. 

 72), chrondroitin-sulphuric acid, oxyproteic acid, alloxyproteic acid, 

 uro ferric acid, thiocyanates and taurine derivatives. The sul- 

 phur content of the bodies just enumerated is generally termed 

 loosely combined or neutral sulphur in order that it may not be con- 

 fused with the acid sulphur which occurs in the inorganic sulphuric 

 acid and ethereal sulphuric acid forms. Ordinarily the neutral sul- 

 phur content of normal human urine is 14-20 per cent of the total 

 sulphur content. 



NH-CH-HN 



ALLANTOIN, 00 



CO. 



NH-CO NH 2 



Allanto'in has been found in the urine of suckling calves as well 

 as in that of the dog and cat. It has also been detected in the urine 

 of infants within the first eight days after birth, as well as in 

 the urine of adults. It is more abundant in the urine of women 

 during pregnancy. Underhill also reports the presence of allantoin 

 in the urine of fasting dogs, an observation which makes it probable 



