150 METHODS FOR THE ANALYSIS OF BLOOD 



provided with a dropping funnel, the delivery tube of the con- 

 denser dipping beneath the surface of the water in a receiving 

 flask. Introduce into the Kjeldahl flask 100 c.c. of water and 1 

 c.c. of glacial acetic acid. Bring the acidified water to a boil and 

 then run the diluted blood in slowly through the dropping funnel. 



Boil for thirty minutes after the last blood is run in. (If 

 /3-oxybutyric acid is to be determined the residue in the Kjeldahl 

 flask should be kept and treated as outlined in the latter part of 

 this procedure.) To the distillate add a little dilute sulphuric 

 acid and redistill. To this distillate add 20 c.c. of hydrogen per- 

 oxide solution and a slight excess of alkali and redistill again. 

 The final distillate is caught in smah 1 Erlenmeyer flasks contain- 

 ing an excess of the Scott- Wilson " acetone reagent " which 

 has been recently filtered. The delivery tube must dip under the 

 surface of the liquid. It is not necessary to distill more than ten 

 minutes to get off all the acetone. Allow to stand for ten to fifteen 

 minutes. Filter through an asbestos mat (filter paper cannot be 

 used as the strong alkali quickly attacks it) in a separable bottom 

 Gooch crucible. Clear filtrates are more readily obtained if the 

 pores of the filter have been partly closed by filtering through it 

 a suspension of talcum powder in water. If the first portions of 

 the filtrate are turbid, refilter. Wash the precipitate with cold 

 water until the washings are free from silver. 



Preparation of the Scott-Wilson Acetone Reagent. The reagent 

 is made up as follows : Mercuric cyanide, 10 gms. ; sodium hydrox- 

 ide, 180 gms. ; water, 1200 c.c. The solution is agitated in a flask 

 and 400 c.c. of a 0.7268 per cent solution of silver nitrate slowly 

 run in. At least 30 C;C. of the reagent must be taken for each 

 milligram of acetone present. , 



(b) Determination of /3-Hydroxybutyric Acid. The residue 

 in the Kjeldahl flask from the above determination is used in the 

 determination of /3-hydroxybutyric acid. While still hot, precip- 

 itate it with about 8 c.c. of 10 per cent sodium carbonate, boil 

 a moment, filter on a Biichner funnel and wash with hot water. 

 To the clear filtrate add 15 c.c. of basic lead acetate (U.S. P.) 

 and 10 c.c. of strong ammonia and make to definite volume 

 (150 c.c.) with water. Allow the precipitate to settle and then 

 filter off on a dry, folded filter. Take an aliquot of the clear 

 filtrate (about 125 c.c.) and boil it to expel the greater part of the 

 ammonia. Cool and add dilute sulphuric acid to precipitate the 



