284 PHYSIOLOGICAL CHEMISTRY 



With the instructions given, the above formulas may be used for direct com 

 putation of the percentage of sugar only, when 0.2 c.c. of blood is used in th< 

 determination. When, however, only o.i c.c. of blood is used, the formulas appb 

 as well, but the value obtained must be multiplied by 2. 



It is better, in cases in which a high sugar content in the blood is suspected (ii 

 diabetes for example) to use only o.i c.c. of blood for the determination. In al 

 other cases 0.2 c.c. of blood should be used. 



8. Acetone Bodies 1 (Acetone, Diacetic Acid and /3-Hydroxybutyric Acid).- 

 Marriott-Scott-Wilson Method. 2 (a) Acetone and Diacetic Acid. Draw 10 c.c 

 of blood from a superficial vein by a sterile graduated syringe and run it into abou 

 40 c.c. of 0.5 per cent potassium oxalate solution. Fit up a Kjeldahl distillatioi 

 apparatus using an 800 c.c. flask, provided with a dropping funnel, the deliver 

 tube of the condenser dipping beneath the surface of the water in a receivinj 

 flask. Introduce into the Kjeldahl flask 100 c.c. of water and i c.c. of glacia 

 acetic acid. Bring the acidified water to a boil and then run the diluted bloo< 

 in slowly through the dropping funnel. 



Boil for 30 minutes after the last blood is run in. 3 To the distillate add a littl< 

 dilute sulphuric acid and redistil. To this distillate add 20 c.c. of hydrogei 

 peroxide solution and a slight excess of alkali and redistil again. The final dis 

 tillate is caught in small Erlenmeyer flasks containing an excess of the Scott 

 Wilson "acetone reagent" which has been recently filtered. 4 The delivery tub 

 must dip under the surface of the liquid. It is not necessary to distil more tha] 

 10 minutes to get off all the acetone. Allow to stand for 10-15 minutes. Filte 

 through an asbestos mat 5 in a separable bottom Gooch crucible. Clear filtrate 

 are more readily obtained if the pores of the filter have been partly closed b; 

 filtering through it a suspension of talcum powder in water. If the first portion 

 of the filtrate are turbid, refilter. Wash the precipitate with cold water unti 

 the washings are free from silver. 



With the aid of a pointed hooked glass rod transfer the precipitate, mat an< 

 crucible bottom to a 50 c.c. beaker, any adhering particles of precipitate beinj 

 washed into the beaker with the aid of about 10 c.c. of "acid mixture." 6 Ad< 

 i c.c. of N/5 potassium permanganate, cover the beaker with a watch glass an< 

 boil until the liquid is colorless. Add more permanganate, a few drops at a time 

 until a persistent brown color is obtained which does not disappear on boiling for i 

 couple of minutes. The brown color is then discharged by the addition of a fe\ 

 drops of strong yellow nitric acid. The greater the amount of acetone presen 

 the more permanganate is required, and it is essential to the accuracy of th< 

 method that an excess be added as indicated above, otherwise the results ar 

 too low. 



Cool the beaker under the tap, add 2 c.c. of saturated ferric alum solution 



1 For nephelometric method see p. 294. 



2 Scott- Wilson: Jour, of Physiol.. 42, 444, 191 1. 

 Marriott: Jour. Biol. Chem., 16, 295, 1913. 



3 If /3-oxybutyric acid is to be determined the residue in the Kjeldahl flask should b 

 kept and treated as outlined in the latter part of this procedure. 



4 The reagent is made up as follows: Mercuric cyanide, 10 grams; sodium hydroxide 

 180 grams; water, 1200 c.c. The solution is agitated in a flask and 400 c.c. of a 0.726 

 per cent solution of silver nitrate slowly run in. At least 30 c.c. of the reagent must b 

 taken for each milligram of acetone present. 



5 Filter paper cannot be used as the strong alkali quickly attacks it. 



6 "Acid mixture:" Nitric acid 40 parts; sulphuric acid, 5 parts; water 55 parts. 



