32 



Scientific Proceedings (78). 



20 (1198) 



A method for the determination of the diastatic activity of the 

 blood with some observations obtained in diabetes and 

 other conditions. 



By J. A. Killian and V. C. Myers. 



[From the Laboratory of Pathological Chemistry, New York Post- 

 Graduate Medical School and Hospital.] 



The procedure introduced by Lewis and Benedict, 1 for the 

 estimation of the sugar of the blood, is utilized in the estimation 

 of its diastatic activity. Two 2 c.c. samples of oxalated blood 

 are taken, and to one of these is added 1 c.c. of 1 per cent, soluble 

 starch solution. Both tubes are now made up to 10 c.c. and 

 incubated at 40 0 C. for 15 minutes. About 0.5 gram of dry 

 picric acid is now added and the mixture stirred. When the 

 proteins are precipitated, the tubes are centrifuged and the super- 

 natant fluid filtered. The sugar in three cubic centimeter portions 

 of the filtrates is now estimated according to the technique 

 described by Myers and Bailey. 2 Correction is made for the sugar 

 originally present in the blood (with the aid of the control) and 

 for the slight reducing action of the soluble starch. The results 

 are recorded in terms of the percentage of the soluble starch (10 

 mg.) transformed to reducing sugars (calculated as glucose) by 

 the 2 c.c. of blood employed. It is believed that under the above 

 conditions, the possible error of glycolysis is a negligible one. 



The diastatic activity of the blood, according to this method, 

 appears to vary from 15 to 25 in a variety of miscellaneous 

 conditions in the human subject, while in diabetes, figures from 

 30 to 70 have been observed. The possible significance of these 

 observations we are not prepared to discuss at the present time. 



1 Lewis and Benedict, Jour. Biol. Chew.., 1915, XX, 61. 

 1 Myers and Bailey, Jour. Biol. Chem., 1916, XXIV, 147. 



