164 COMPOSITION OF THE BODY 



timated by determining the total nitrogen content and multiplying 

 the result by the factor 6.25. The determination of the nitrogen 

 should be done in accordance with the Kjeldahl method, which 

 is described in nearly all works on volumetric analysis. 



230. Tests for Albumin. The nitrate from the material from the 

 dialyzers may now be examined. It may contain albumin, pro- 

 teose and peptone, as these substances are all soluble in water, 

 and should not be precipitated by the removal of the salt. 



1. Try the, color reactions (page 162) on portions of the fluid. 



2. Coagulation test. Apply as directed for globulin. Veg- 

 etable albumins coagulate at about 65— 70 C. Heat the re- 

 mainder of the filtrate until the coagulable proteid is all thrown 

 down. Collect the coagulum on a filter, wash with alcohol and 

 ether, and dry as directed for globulin. The albumin will 

 undergo decided changes during this process, and it will be prof- 

 itable to note some of its properties as coagulated proteid. 



(«) Test solubility in water, dilute alkalies and dilute acids. 

 (3) Boil for some time with very dilute acid or alkali. It should 

 be dissolved slowly. 



(c) Test with strong acid or alkali. It is quickly decom- 

 posed. 



(d) Test it with a solution of pepsin to which are added a few 

 drops of hydrochloric acid. Keep at a temperature of 40 C. 

 The coagulated proteid becomes hydrolyzed by the enzyme and 

 is dissolved. Filter the solution and neutralize with sodium hy- 

 drate. Acid albuminate is precipitated, unless all has been trans- 

 formed to proteoses and peptones. 



231. Treatment of Proteoses. The filtrate obtained in the sepa- 

 ration of the coagulum may contain proteoses and peptones. 

 Test the fluid for proteoses by the color reactions. If positive 

 results are obtained saturate the filtrate at boiling point with am- 

 monium sulphate, which will precipitate all proteoses. The pep- 

 tones still remain in solution. The precipitates having been 

 removed by filtering and dissolving in water the ammonium sul- 

 phate may be removed by dialysis, or by the addition of barium 



