220 



Messrs. F. P. Knowlton and E. H. Starling. [Mar. 26; 



From these results we may conclude that the normal heart fed with 

 normal blood under approximately physiological conditions consumes about 

 4 mgrm. of sugar per hour and per gramme of heart muscle. 



II. The Consumption of Sugar in the Diabetic Heart. 

 Similar experiments were carried out on the hearts of dogs from which 

 the pancreas had been removed from three to six clays previously. The 

 following table represents the results obtained in six such experiments : — 



Sugar Consumption in Diabetic Heart. 



Sugar in serum. 



Milligramme 



Before. 



After 1 hr. 



sugar per grm. heart 

 per hour. 



per cent. 



per cent. 





0-59 



0-60 







0-30 



0-24 



1-1 



74 



0-74 







0-57 



-54 (H hrs.) 



1-0 



0-53 



0-52 



0-5 



0-50 



0-49 



5 



It will be seen that the consumption of sugar was very much less than in 

 normal hearts. In two cases the sugar titration gave the same results at the 

 beginning and at the end of the hour. In two other cases a difference in 

 titration was obtained which pointed to a consumption of sugar of 0'5 mgrm. 

 per gramme of heart muscle. 



But this difference was within the limits of our experimental error. 

 A series of parallel estimations of sugar in different samples of serum gave 

 the following results : — 



Blood 



i. 



2. 



3. 



4. 



5. 



Sample A 



„ B 



per cent. 

 0-63 

 0-62 



per cent. 

 0-61 

 0-62 



per cent. 

 0-365 

 0-37 



per cent. 

 0-36 

 0-38 



per cent. 

 0-37 

 0-37 



The average experimental error was therefore 001 per cent., and the 

 maximal error 0'02 per cent. Moreover, we have evidence of the occurrence 

 of a certain small amount of glycolysis in the blood itself. This in normal 

 blood was probably not greater than 0"01 per cent, per hour during the first 

 two hours of the experiment. In diabetic blood taken at the end of the 

 experiment a somewhat higher degree of glycolysis was occasionally observed 



