176 METHODS FOR THE ANALYSIS OF BLOOD 



Inorganic Phosphoric Acid. 10 c.c. of the filtrate ( = 1 c.c. of 

 original blood) are measured into a 25 c.c. glass-stoppered flask, 

 made to the mark with water, and mixed. The standard is pre- 

 pared by measuring 3 c.c. of the standard phosphate solution 

 (0.09 mg. of HsPCU) into a similar flask, adding 8 c.c. of the acid 

 ammonium sulfate (to balance the salt content of the test solution), 

 filling to the mark with water, and mixing. Determinations are 

 made with 5 c.c. of this dilution as in total phosphates. 



Acid-Soluble Phosphoric Acid. 2 c.c. of the filtrate (0.2 c.c. 

 of blood) are measured into one of the large test-tubes, glass beads 

 and 1.5 c.c. of the sulf uric-nitric acid mixture added, and the 

 whole is digested with heat in the same way as for total phos- 

 phates, except that since the amount of organic material is very 

 small, the first stage of heating may be passed over quickly. The 

 neutralization and subsequent treatment are the same as for 

 total phosphates. For a standard solution measure 3 c.c. of the 

 standard phosphate solution (0.09 c.c. of HsPC^) into a 25 c.c. 

 glass-stoppered flask, add about 1.5 c.c. of the acid ammonium 

 sulfate and the amount of alkali used in neutralizing the test 

 solution. Neutralize with acid as usual, then make to the mark 

 and mix. Subsequent treatment is as with total phosphates. 



Other Forms of Phosphoric Acid. Obtained by subtracting 

 inorganic from acid-soluble phosphoric acid. 



Plasma 



Three c.c. of plasma are run slowly into 20 c.c. of the acid ammo- 

 nium sulfate solution in a 25 c.c. glass-stoppered graduated flask, 

 the volume is made to the mark with water, the whole mixed, and 

 let stand with occasional shaking for at least ten minutes. It is 

 then filtered. After the filter has drained, it should be folded in 

 the funnel and pressed out with a clean stirring rod to get as 

 much filtrate as possible. The filtrate is clear and colorless and 

 contains no detectable protein. With this filtrate determinations 

 are made of inorganic and acid-soluble and other forms as before. 



Inorganic. (a) 10 c.c. of the filtrate ( = 1.2 c.c. of plasma) are 

 measured into one of the 25 c.c. flasks and made to the mark 

 with water. A standard is prepared by adding to another flask 

 3 c.c. of the standard phosphate (0.09 mg. of HsPC^) and acid 

 ammonium sulfate equal to that present in the test solution (8 



