256 PANCREATIC DIABETES 



normally to produce a glycolytic ferment, which is missing 

 in the depancreatized animal, for which reason the animal is 

 unable to bring the sugar to its usual catabolism ; the sugar, 

 therefore, accumulates in the blood and thence passes into 

 the urine. The original idea in this theory which would seek 

 to place glycolysis normally in the blood, has been prac- 

 tically altogether given up; our present conception is that 

 the sugar undergoes its destructive changes for the most 

 part in the fixed tissues, not in the blood. 



Otto Cohnheim 24 believes he has evidence from studies 

 upon the expressed juices of tissues that muscle contains 

 an enzyme which is capable of inducing combustion of grape- 

 sugar to carbonic acid ; which however does not exist in the 

 muscle in active form for the most part, but requires for ac- 

 tivation a material arising in the pancreas and passed thence 

 into the blood stream, a i i pancreatic activator. ' ' Occasion 

 will be taken later, in summing up our conclusions upon gly- 

 colysis, to discuss the objections which have been made to 

 Cohnheim 's experiments. 



In view of the undoubtedly very great difficulty of posi- 

 tively excluding interference from bacterial processes in 

 experiments with expressed juices, it is a matter for special 

 congratulation that certain recent comparative experiments 

 upon the consumption of sugar by the normal and by the 

 diabetic heart by one of the best of our living biological 

 experimenters, E. H. Starling, 25 are available. By an in- 

 genious experimental mechanism he has succeeded in 

 arranging a heart and lung preparation 26 so as to keep a 

 dog's heart beating for hours, working at normal arterial 

 pressure and maintaining the normal amount of blood in 



"0. Cohnheim, Zeitschr. f. physiol. Chem., 89, 396, 1903; 42, 401, 1904; 

 47, 253, 1906. 



25 F. P. Knowlton and E. H. Starling (Univ. College, London), Centralbl. f. 

 Physiol., 26, 169, 1912; Jour, of Physiol., 45, 146, 1912. 



* Cf. E. Jerusalem and E. H. Starling, Jour, of Physiol., 40, 299, 1910. 



