290 



PHYSIOLOGICAL CHEMISTRY 



To secure accurate results the method of Bang must be rigidly con- 

 trolled, all new solutions and absorbent papers being checked up 

 against pure 0.2 per cent glucose solutions. Taylor and Hulton 1 

 also suggest the following precautions. A blank check must be made 

 on the reagents each day an estimation is made. 0.10-0.15 gram of 

 blood should be taken and must spread smoothly on the paper. The 

 proteins are best coagulated by heating of the blood-impregnated 

 papers in the hot air oven at 100 (as recommended by Gardner and 

 McLean) 2 for five minutes with corks of flasks inverted. The solu- 

 tion should be boiled four minutes for complete reduction. The 

 iodine solution must be fresh each day and checked each day. Deter- 

 minations should be made in triplicate. Results cannot be depended 

 upon to be more accurate than to 0.005 gram glucose in 100 c.c. blood. 

 Other authors have recommended that an hour instead of half an hour 

 be allowed for the diffusion of the blood sugar, the fluid being brought 

 to the boiling-point twice during this period or kept in a bath at 40 C. 



BLOOD 



SUGAR 



PER 

 CENT 



0.24 



0.22 



0.20 



0.18 



0.16 



0.14 



0.12 



Q.1Q 



Q.Q8 



lai hr. 



2nd hr, 



8rd hr 



NORMAL 



HVPERTHYRO I ISM AODISON's DISEASE 



FIG. 92. SUGAR TOLERANCE CURVES. 

 (Myers: "Practical Chemical Analysis of the Blood," 1921). 



(c) Carbohydrate Tolerance Test (Killian). 1 Principle. Blood 

 sugar is determined at hourly periods following the ingestion of 1.75 gm. 

 of glucose per kilogram of body weight. Urinary sugar for the 24 hour 

 period following the ingestion of the glucose is also determined. 



Baylor and Hulton: Jour. BioL Chhm., 22, 63, 1915. 

 2 Gardner and McLean: Bicchem,J., 8, 391, 1914. 

 'Killian: Proc. Sor. Exper. BioL and Med., 17, 91, 1920. 



