194 THE URINE. 



of a renal haemorrhage. This may occur in Bright's dis- 

 ease, also with malignant renal growths or renal calculi. 



If the haemorrhage is from the bladder the urine is 

 often alkaline, and clots of blood are common. It may be 

 caused by vesical calculi, by cystitis or villous growths, and 

 by carcinoma. 



407. Add a very little blood to highly-colored nor- 

 mal urine, and notice that the bands of oxyhgemoglobin 

 are visible through the spectroscope, although to the eye 

 there may be no indication of its presence. If the urine 

 is too turbid to examine with the spectroscope, it should 

 be filtered, and if the residue is reddish on the paper this 

 should be washed with 5 cubic centimeters of water and 

 the washings examined. 



408. Convert the oxyhasmoglobin into haemoglobin 

 as in Experiment 246, and notice that the two bands 

 change to one. 



409. To urine containing a small amount of blood 

 add enough sodium hydrate to make alkaline, and heat 

 to boiling. The phosphates of the alkaline earths will be 

 precipitated, and the precipitate will be colored reddish by 

 the haematin from the decomposed haemoglobin. If no 

 blood were present the precipitated phosphates would be 

 white. This test will detect very small amounts of blood 

 in urine. If the liquid is very dark colored, it may be 

 necessary to filter and wash the precipitate before its color 

 can be determined. 



410. Examine microscopically the sediment from a urine 

 after recent haemorrhage. Observe the presence of red corpuscles 

 and also the change in their form which takes place after standing. 



The guaiacum-hydrogen peroxid test (249) can also be em- 

 ployed, but its fallacies should not be lost sight of. 



