178 THE URINE. 



not colored, separating the two liquids by means of a glass-stop- 

 pered funnel. Distill the chloroform from its solution, dry the 

 residue on a water-bath and wash it with hot water, passing this 

 through a small filter to avoid the loss of indigo. Dry the paper, 

 extract it with warm chloroform, add this to the washed residue 

 and distill off the chloroform. Warm the indigo on a water-bath 

 for five to ten minutes with concentrated sulphuric acid and pour 

 it into .about 100 cubic centimeters of water, rinsing the vessel 

 with a little more water. Filter and titrate with a standard 

 solution of potassium permanganate until the color is colorless or 

 yellowish. 



The permanganate contains about 0.1 gram to the liter. 

 It must be frequently standardized against a solution of oxalic of 

 known strength. The indigo blue corresponding to each cubic 

 centimeter is 1.04 times the weight of the oxalic acid used. From 

 this the weight of indican can be calculated. 



ALBUMINOUS COMPOUNDS OF THE URINE. 



The principal albuminous substance occurring in the 

 urine is serum-albumin. Besides this there may be found 

 there serum-globulin, albumose, fibrin, and possibly pep- 

 tones. The nucleoalbumins also are not uncommon, being 

 often mistaken for mucin. 



ALBUMINURIA. 



Serum-albumin may find its way into the urine either 

 from the kidneys (renal albuminuria) or from serous 

 liquids,- like blood, pus, or lymph, mixing with it at 

 some point in the urinary tract below the kidneys. When 

 it is due to degenerative changes in the kidney it is usually 

 accompanied by epithelium from the tubules, often in the 

 form of cylinders or casts. Changes in the composition 

 of the blood or in the blood-pressure may allow albumin 

 to pass through the kidney. This is seen in anaemic con- 



