THE BIOCHEMISTRY OF RESPIRATION 255 



muscle press juice, or with pancreas juice, in presence of toluol, 

 little or none of it disappeared. If, on the other hand, fresh 

 muscle and pancreas were minced together, the mixed juice 

 squeezed out from the two tissues possessed distinct glycolytic 

 power. Extracts of boiled pancreas, if mixed with muscle juice, 

 were as efficient as those of fresh pancreas, so the activating 

 power of the pancreas was not dependent on an enzyme. 

 Though these experimental results have been contradicted by 

 some investigators, they have been confirmed in the main, 

 especially by Hall. 1 Other investigators have found that 

 glycolytic power is not confined to the muscles and pancreas. 

 Liver possesses it too, and is able to act to some extent in the 

 absence of the pancreas. The special glycolytic power attributed 

 to the pancreas is founded on the well-known discovery of 

 v. Mering and Minkowski that extirpation of the pancreas causes 

 diabetes. This was generally supposed to prove that the 

 pancreas forms an internal secretion which enables the tissues, 

 especially the muscles, to burn up sugar ; but the recent work 

 of Starling and Patterson 2 upon the sugar consumption of the 

 heart of dogs suffering from diabetes as the result of pancreas 

 extirpation, proves that there is very little loss of glycolytic 

 power. The internal secretion of the pancreas appears rather 

 to prevent the over-production of sugar by the organism than to 

 stimulate its consumption, so the experiments on glycolysis 

 in vivo show no correspondence with those made with tissue 

 juices and extracts in vitro. 



It should be pointed out that in most of the observations on 

 the glycolytic power of animal tissues the evidence of glycolysis 

 consisted only in the disappearance of some of the sugar added. 

 Still some investigators 3 found that C0 2 was evolved. Levene 

 and Meyer 4 maintain that the disappearance of sugar on incuba- 

 tion with muscle plasma and pancreas extract is due to a con- 

 densation of the glucose molecule rather than to its degradation. 

 They found that some of the sugar was converted into a biose, 

 and that if the mixture were boiled with dilute acid its original 

 reducing power was restored. 



1 Hall, Amer. Journ. Physiol. 18, p. 283, 1907. 



2 Starling and Patterson, Journ. Physiol. 47, p. 137, 1913. 



3 Cf. Arnheim and Rosenbaum, Zeit. f. physiol. Chem. 40, p. 220, 1903, and 

 Feinschmidt, Hofmeister Beitr. 4, p. 511, 1904. 



4 Levene and ~Meyer,/oum. Biol. Chem. 9, p. 97, 191 1. 



