128 LABORATORY WORK IN PHYSIOLOGICAL CHEMISTRY. 



NaOH and heat it. The oxyhamoglobin is split into hsematin 

 and protein, and the earthy phosphates being precipitated, 

 drag down the hsematin with them. Filter off the precipi- 

 tate, which should be of a brownish color, and after drying it, 

 try to obtain Teichmann's crystals (p. 76). 



(d) Struve's Test. Make a portion of the urine alkaline 

 with NaOH and precipitate with tannic acid. Test this pre- 

 cipitate for hsemin. 



METH^EMOGLOBIN. 



Examine the urine with the spectroscope, add a few drops 

 of NH 4 OH and filter; a two-banded spectrum appears similar 

 to that of oxyhsemoglobin. Do not confound the spectra of 

 methsemoglobin and of hsematin in acid solution. 



HvEMATIN. 



1. Examine in the spectroscope. If a single band is 

 present add (NH 4 ) 2 S to the urine, filter, and again examine it. 

 The two bands of reduced hsematin should appear. 



2. Make tests c and d under Oxy hemoglobin. 



ILEMATO PORPHYRIN. 



The preparation of this substance from the urine for the 

 purposes "of identification and spectroscopic examination is 

 as follows: 



Method of Garrod.To 100 c.c. of urine add 20 c.c. of 

 10 per cent NH 4 OH. The phosphates of the earthy metals 

 are precipitated and with them the haematoporphyrin. This 

 precipitate is filtered off, washed, and warmed in a flask with 

 acidulated alcohol. The pigment goes into solution. Use 



