174 C. M. BROOMALL : 



establish a satisfactory theory. In view of this, therefore, it 

 may not be altogether presumptuous on the part of the lay 

 student to venture a few suggestions looking toward some such 

 correlation. 



A theory such as is needed is one that explains — first, the 

 conversion of sugar into glycogen ; second, the reconversion 

 of glycogen into sugar, and third, the oxidation of the sugar. 

 In considering the subject it will be well to take up these 

 various branches one by one and endeavor to see what aid 

 kindred lines of research can offer toward the explanation of 

 the phenomena, and especially let us inquire into the part 

 which may be played by enzymes in the process. 



L,et us take up, in the first place, the conversion and 

 storage of the sugar as glycogen. The principal localities 

 where this occurs, as stated above, are the liver and the 

 muscles. There seems no way of accounting for the conver- 

 sion of glucose into glycogen other than to attribute it to the 

 direct action of the living cells. The change being a sj^n- 

 thetic one, we cannot appeal to an}^ theorj- of simple chemical 

 reactions or theory of unorganized ferments to aid us, as such 

 reactions and ferments tend to produce analytic or catabolic 

 processes. In the present state of knowledge, therefore, this 

 change from glucose to glycogen in the liver and muscles can 

 only be explained as a direct result of the activity of the 

 living cells. 



Consider now the reconversion of glycogen into glucose. 

 It has been found by a number of observers that there can be 

 obtained b}- extraction from the liver and also from the 

 muscles an unorganized ferment or enzyme, which has the 

 power of transforming glycogen into glucose. Observations 

 by Von Wittich, Claud Bernard, Kaufman, Pavy and many 

 others have established without question the existence of such 

 a ferment in the liver. This ferment exists in that organ in 

 the form of a zymogen always read}- to release the active 

 ferment under proper stimulus. Likewise Nasse, Halliburton 

 and others have obtained from the muscles a similar glyco- 



