BLOOD AND HEMOGLOBIN IN THE URINE. 



499 



and carry down with them hemochromogen, so that garnet-red flakes are de- 

 posited. When the urine contains but a small amount of blood, these flakes 

 appear red in reflected light and greenish in transmitted light, the distinction 

 being clear when as little as one part of hemoglobin is present in a thousand. 

 If the earthy phosphates are already precipitated in alkaline urine, deposition 

 is effected artificially by addition of a few drops of magnesium sulphate and 

 ammonium chlorid, and the same change in color is apparent. 



4. From the earthy phosphates thus obtained, containing hemoglobin, and 

 collected upon a filter, hemin-crystals can be prepared. For this purpose the same 

 procedure may be followed as is described on p. 62. 



5. The reaction may be tested, also, with tincture of guaiac and oil of tur- 

 pentine, the blood acting as a carrier of ozone. The urine should not lose the 

 property of developing a blue color as a result of previous heating. 



6. Urine containing blood when examined with a spectroscope exhibits 

 characteristic appearances. The arrangement of the apparatus is shown in Fig. 

 161. The urine is placed in the chamber D (hematinometer) i cm. thick, with 

 parallel glass walls. Through this pass the rays of light from a lamp, E, while 



FIG. 161. Spectroscope for Examination of the Urine as to the Presence of Hemoglobin. 



another, F, illuminates a scale, and the observer makes his observation through 

 the telescope, A. The examination yields the following results: 



(a) Fresh urine containing blood exhibits the spectrum of oxyhemoglobin (Fig. 

 15). Under some circumstances, it is necessary, in this connection, to dilute the 

 urine with distilled water and to secure perfect clearness by filtration. To con- 

 firm the observation, the oxyhemoglobin may be exposed to the action of reducing 

 substances, which produce reduced hemoglobin. 



(6) If concentrated urine containing blood is permitted to stand for a some- 

 what longer time, especially at the temperature of the blood, it acquires a deep, 

 dark-brown color, like coffee-grounds, in the presence of an acid reaction. The 

 hemoglobin is thus converted into methemoglobin. Methemoglobin in solution is, 

 in contradistinction from oxyhemoglobin, precipitable by lead acetate. The acid 

 solution of methemoglobin in urine thus resulting exhibits in the spectroscope a 

 close resemblance to hematin in acid solution (Fig. 15). If the urine is now 

 rendered alkaline, the absorption-bands of methemoglobin in alkaline solution 

 appear. The spectra of oxyhemoglobin and methemoglobin are also found com- 

 bined in the urine. When treated with reducing substances methemoglobin is 

 transformed into hemoglobin. Later on, also hematin is present in acid solution 

 in the urine. If such urine is treated with reducing substances, alkaline hematin 

 appears. 



