152 METHODS FOR THE ANALYSIS OF BLOOD 



A similar solution of the standard is prepared by adding 5 c.c. 

 of the standard fatty acid solution from a pipette with stirring to 

 50 c.c. of distilled water. To the standard and to the test solutions 

 are added simultaneously from pipettes and with stirring 10 c.c. 

 portions of dilute (1:3) hydrochloric acid and the solutions allowed 

 to stand for five minutes, after which they are transferred to the 

 comparison tubes of the nephelometer. Several readings should 

 be taken and averaged. The standard tube should always be on 

 the same side. See discussion of nephelometer (page 146) for 

 details as to reading. The results represent the amount of total 

 fat (fatty acids and cholesterol) in the blood, expressed as oleic 

 acid. The fat of the corpuscles is not completely extracted, and 

 it should be borne in mind that other lipoids as cholesterol are 

 included in the results. Cholesterol may be determined separately 

 and subtracted from the result for total fat. It may also be 

 determined in a part of the blood extract as prepared above by 

 a modified Autenrieth-Funk procedure (see page 156). Methods 

 have also been devised for the determination of the phosphatides 

 of blood (see page 171). 



BLOOD ACETONE BODIES 



Determination of Acetone Bodies. Method of Van Slyke and Fitz l 



Principle. The principle is identical with that for the deter- 

 mination of acetone bodies in urine after the removal of the 

 proteins from the blood. 



Procedure. Whole Blood. Ten c.c. of whole blood are diluted 

 with about 100 c.c. of water in a 250 c.c. flask, and 20 c.c. of the 10 

 per cent mercuric sulphate are added. (73 gms. of red mercuric 

 oxide dissolved in 1 liter of 4 N sulphuric acid.) The solution is 

 shaken for a moment,until the protein coagulates, and is then diluted 

 with water up to the 250 c.c. mark. After fifteen minutes or 

 longer it is filtered through a dry folded filter. If the first drops 

 are cloudy they are passed through a second time. The filtrate 

 has a slight pink tinge, but the substance responsible for it does 

 not precipitate when boiled with mercuric sulphate, nor other- 

 wise interfere with any of the acetone body determinations. 

 1 Van Slyke and Fitz: Jour. Biol. Chem., 1917, 32, 495. 



