URINE 429 



If the urine under examination contains albumin the greater portion of this 

 substance should be removed by boiling the urine before testing it for the pres- 

 ence of nucleoprotein. 



2. Tannic Acid Precipitation Test (Ott). Mix 25 c.c. of the urine with 

 an equal volume of a saturated solution of sodium chloride and slowly add 

 Almen's reagent. 1 In the presence of nucleoprotein a voluminous precipitate 

 forms. 



BLOOD 



The pathological conditions in which blood occurs in the urine may 

 be classified under the two divisions hematuria and hemoglobinuria. 

 In hematuria we are able to detect not only the hemoglobin but the 

 unruptured corpuscles as well, whereas in hemoglobinuria the pig- 

 ment alone is present. Hematuria is brought about through blood 

 passing into the urine because of some lesion of the kidney or of the 

 urinary tract below the kidney. Hemoglobinuria is brought about 

 through hemolysis, i.e., the rupturing of the stroma of the erythrocyte 

 and the liberation of the hemoglobin. This may occur in scurvy, 

 typhus, pyemia, purpura, and in other diseases. It may also occur as 

 the result of a burn covering a considerable area of the body, or may 

 be brought about through the action of certain poisons or by the in- 

 jection of various substances having the power of dissolving the 

 erythrocytes. Transfusion of blood may also cause hemoglobinuria. 



Even in true hematuria the erythryocytes may escape detection if 

 the urine is ammoniacal inasmuch as the cells disintegrate under these 

 conditions. 



EXPERIMENTS 



1. Potassium Hydroxide Test (Heller). Render 10 c.c. of urine strongly alka- 

 line with potassium hydroxide solution and heat to boiling. Upon allowing the 

 heated urine to stand a precipitate of phosphates, colored red by the contained 

 hematin, is formed. It is ordinarily well to make a " control " experiment using 

 normal urine, before coming to a final decision. 



Certain substances, such as cascara sagrada, rhubarb, santonin, and senna, 

 cause the urine to give a similar reaction. Reactions due to such substances 

 may be differentiated from the true blood reaction by the fact that both the pre- 

 cipitate and the pigment of the former reaction disappear when treated with 

 acetic acid, whereas if the color is due to hematin the acid will only dissolve the 

 precipitate of phosphates and leave the pigment undissolved. 



2. Teichmann's Hemin Test. Place a small drop of the suspected urine or a 

 small amount of the moist sediment on a microscopic slide, add a minute grain 

 of sodium chloride and carefully evaporate to dryness over a low flame. Put a 

 cover-glass in place, run underneath it a drop of glacial acetic acid, and warm 

 gently until the formation of gas bubbles is observed. Cool the preparation, 

 examine under the microscope, and compare the form of the crystals with those 



1 Dissolve 5 grams of tannic acid in 240 c.c. of 50 per cent alcohol and add 10 c.c. of 25 

 per cent acetic acid. 



