PHOSPHORIC ACID IN BLOOD 175 



It should be left in the bath a few minutes after it is apparently 

 dry to remove traces of alcohol which would interfere with the 

 subsequent oxidation. 1.5 c.c. of the sulfuric-nitric acid mixture 

 are added, distributed by shaking to the material on the sides 

 of the tube, and the mixture is digested in the same way as directed 

 for total phosphates, 



Plasma 



Two c.c. of plasma are measured into 35 to 40 c.c. of alcohol- 

 ether in a 50 c.c. flask as described above and the whole 

 process is carried out as for whole blood. For the determination 

 15 c.c, is required (0.6 c.c. of plasma), 



Corpuscles 



Corpuscles are hemolyzed by dilution with an equal volume 

 of warm water and allowed to stand for ten minutes, then 3 c.c. 

 of the dilution are measured into 35 to 50 c.c. of alcohol-ether 

 in a 50 c.c. flask and treated as with whole blood. There is 

 a tendency for the corpuscular precipitate to mass together when 

 it settles out and the flask should be well shaken occasionally 

 during a half hour after which the extraction may be proceeded 

 with as before. For the determination 10 c.c. of the extract (0.3 

 c.c. of corpuscles) are used. 



Acid-Soluble Phosphoric Acid Inorganic and Other Forms 

 Whole Blood 



The blood is first laked by the addition of an exactly equal 

 volume of warm (40 C.) water and allowed to stand for about ten 

 minutes with occasional shaking. Of this mixture 5 c.c. are meas- 

 ured with a pipette into 15 c.c. of acid ammonium sulfate (see 

 acid ammonium sulfate in the notes below, page 178) in a 25 c.c. 

 glass-stoppered graduated flask. The blood is added slowly and 

 the liquid in the flask kept rotating during the addition, after 

 which the flask is filled to the mark with the ammonium sulfate, 

 well mixed and let stand with occasional shaking for at least ten 

 minutes. The liquid is then filtered through a phosphate-free 

 filter. The filtrate is clear, colorless, and free from protein. In 

 this filtrate determinations are made of acid-soluble, inorganic, 

 and, by difference, other forms of phosphoric acid. 



