66 PHYSIOLOGICAL AND PATHOLOGICAL CHEMISTRY. 



a dry flask and pour ether over it (or, better, grind it iii a 

 mortar with ether and then put the mixture into a flask), 

 shake vigorously, let stand for some time, then filter, and 

 wash with ether. Then grind 0.3 to 0.5 g. of the dry precipi- 

 tate with thirty times its weight of a mixture of three parts 

 of potassium nitrate and one part of sodium carbonate and 

 fuse the mixture. (See in this connection the test for phos- 

 phorus in casein in the chapter on Milk, page 9.) 



The presence of phosphoric acid in the fused mass shows 

 that we have to do with nucleoalbumin. It is advisable to 

 make a part of the nitric acid solution of the fused mass alka- 

 line with ammonia : no cloudiness due to calcium phosphate 

 and no crystalline precipitate of ammonium magnesium phos- 

 phate should appear. Since, however, the complete removal 

 of calcium phosphate is only accomplished with great diffi- 

 culty, no attention should be paid to the presence of a trace 

 of phosphoric acid in the fused mass. This may come from 

 the calcium phosphate, or also from traces of adhering lecithin. 

 If we wish to be quite sure of the absence of lecithin, it is 

 recommended to treat the product once more with hot abso- 

 lute alcohol before fusing it with the oxidizing mixture, evap- 

 orate the alcoholic extract to dryness, and fuse the residue 

 with soda and saltpeter. In this fused mass there must be 

 no phosphoric acid. 1 



III. Examination for Serum Albumin and Globulin. 



This is done according to the method given under Blood- 

 serum, page 58. 



IV. Examination for Urea. 



Exactly neutralize 100 cc. of the fluid with acetic acid, 

 then pour into 400 cc. of 95 per cent, or absolute alcohol, 



1 In regard to the detection of the xanthine bases and the pentose 

 group, which is present in very many nucleoalbumins, see the chapter on 

 Pancreas, page 76. 



