32 PHYSIOLOGICAL AND PATHOLOGICAL CHEMISTRY. 



Digest for two to three days at 40, shaking repeatedly and thor- 

 oughly, then filter and drain the residue completely by pressure. 

 Heat the extract in order to coagulate the albumin, evaporate the 

 filtrate to about 500 cc., make strongly alkaline with ammonia, and 

 precipitate with ammoniacal silver solution, etc. By means of the 

 digestion the nuclein is decomposed and the substances which prevent 

 the precipitation of the hypoxanthine silver are removed. 



V. DETECTION OF ORGANICALLY COMBINED PHOSPHORUS IN 

 MEAT EXTRACT. 



According to Siegfried, meat extract free from albumin 

 contains an organic substance (nucleon) in which phosphorus 

 is present. Carniferrin is the name given by Siegfried to the 

 iron compound of this substance. The following method 

 may be used for the preparation of this compound : Dissolve 

 10 g. of meat extract in 200 cc. of water, make faintly alka- 

 line with ammonia, add calcium chloride solution as long as 

 a precipitate forms (the reaction must remain neutral during 

 the precipitation and later a little more ammonia is to be 

 added), and filter. To the filtrate add 15 cc. of a 3 per cent, 

 ferric chloride solution, heat to boiling and, if necessary, 

 neutralize exactly with ammonia. The precipitate is fil- 

 tered off and washed. It dissolves in dilute sodium car- 

 bonate solution, forming a more or less clear solution. The 

 remainder of the carniferrin is ground with alcohol, filtered, 

 and then treated with a small quantity of ether. The pres- 

 ence of the phosphorus may be shown by fusing with the 

 oxidizing mixture, dissolving the fused mass in water, filter- 

 ing from the iron oxide, and testing for phosphoric acid in 

 the filtrate. 



