84 PHYSIOLOGICAL AND PATHOLOGICAL CHEMISTRY. 



(a) Phloroglucin Test. Pour on a very small quantity of 

 the substance a few cubic centimeters of hydrochloric acid, 

 add a little phloroglucin, and heat to boiling: cherry-red 

 color, then turbidity. Let cool somewhat, shake with an 

 equal volume of amyl alcohol, and examine this with the 

 spectroscope: absorption-band between D and E. 



(6) Orcin Test. Instead of phloroglucin take a few orcin 

 crystals and proceed in the same way: reddish-blue color, 

 then precipitation of a blue pigment. The amyl alcohol turns 

 red and after some time emerald-green. Examine with the 

 spectroscope: absorption-band between C and D. 



If somewhat larger quantities (not less than 0.2 g.) of the 

 nucleoproteid are available, the presence of the guanine may 

 also be shown. Heat in a flask, cautiously and shaking con- 

 stantly, with about 25 cc. of a mixture of one volume of hydro- 

 chloric acid and three volumes of water. Keep boiling gently 

 about fifteen minutes, neutralize with caustic soda solution, 

 acidify with acetic acid, and let stand till next day: guanine 

 will separate. In the filtrate the phosphoric acid may be 

 detected by means of uranium acetate, the pentose by means 

 of the Trommer's test and the pentose tests given above. 



