I9I4] 



S. Gitlow and B. Horowit:: 



273 



In spite of the difficulty of getting perfect colorless controls, the 

 method was further studied in an attempt to utilize it for compara- 

 tive tests, as for example, in the comparison o£ the color of a 

 Standard sugar Solution which had been treated with the MoHsch 

 reagents with that of blood treated similarly; or the differentiation 

 of normal from diabetic urine. Whilst it is true that the intensity 

 of the coloration is proportional to the concentration of the carbo- 

 hydrate, and that the dement of time is a factor that cannot be 

 neglected, two other important points have to be considered: the 

 Order in which the reagents are mixed, and the amount of water 

 present. The reagents are best added in the following order: 

 a-naphthol, Solution to be tested (or vice versa), water, sulfuric 

 acid. As heat accelerates the velocity of the reaction, and water 

 and sulfuric acid produce heat, it is evident that the amount of 

 water added (as well as that of sulfuric acid) must be the same 

 throughout. 



Several kinds of blood have been tested : Guinea pig (ear lobe) 

 and human (apparently normal, also made artificially hyperglycemic 

 by the addition of glucose, and diabetic). The guinea-pig blood 

 was diluted with ten volumes of water. A series of tests was made 

 containing successively i, 2, 3, 4, 5, 6, 7, 8, 9 drops of this diluted 

 blood in test tubes. Controls with no blood, one with no a-naphthol 

 and a sugar control were made, thus : 



Number of the test 



Diluted blood (drops) 



a-naphthol sol. (drops) .... 



Water (drops) 



Sulfuric acid sol. (c.c.) 



Glucose sol. — I : loo (drop) 



X 



14 



2 



I 



Control I gave no pink color. Control 11 gave a green color, 

 which changed to light brown with the addition of more blood. 

 The intensity of the pink color increased with the quantity of the 

 blood taken. The color of the sugar control (12) corresponded 

 with the color between 2 and 3. This corresponds to a dilution of 

 o.i per Cent of glucose. The addition of sugar (i-ioo sol.) to the 

 blood intensifies the color proportionately. 



Two c.c. of sulfuric acid Solution had to be used with the blood 



