42 SCIENCE PROGRESS 



utilisation only, we can perhaps understand that if a process 

 which necessarily precedes utilisation {supra) be slowed by 

 a deficiency in the chemical mechanism, an effort to increase its 

 velocity by increasing the concentration round the cell would 

 follow. Von Noorden speaks of the cells in diabetes as con- 

 tinuously feeling the need of sugar, though surrounded by the 

 ample supply which they are unable to use. They still send 

 out, therefore, those normal chemical stimuli which lead to the 

 mobilisation of sugar and the supply continues in spite of the 

 failure to utilise it. Pavy rejected this conception of a "call" 

 made by sugar-hungry cells. So long indeed as diabetes 

 involves only a failure in assimilation of the carbohydrate eaten, 

 there is no need for any such assumption and, in any case, it is 

 not a very satisfactory one. But when a large production 

 of sugar from protein is established and continues, in spite 

 of the excess of sugar circulating, some explanation of the fact 

 seems called for. 



Von Noorden's assumption, in so far as it involves a para- 

 doxical " call " for sugar when so much is available, is perhaps 

 unnecessary. We have seen that the diabetic organism liberates 

 approximately as much energy under given conditions as does 

 the normal organism under similar conditions. As this energy 

 in the case of the former is obtained to a very much smaller 

 extent from carbohydrate, it must be got from proteins and fat. 

 If now it be a normal thing, as most assume and as Von 

 Noorden assumes, for a certain fraction of the protein molecule 

 to pass through the stage of sugar during its breakdown in the 

 body, then that fraction is unavailable for the diabetic animal, 

 which in so far as it makes use oi protein to yield energy must 

 rely upon the residuum of the molecule which does not pass 

 through the sugar stage. But on the above assumption, the 

 breakdown which yields this residuum must also yield sugar, 

 even if it occur on perfectly normal lines. The call of the 

 tissues, therefore, is not for sugar but for energy and the con- 

 tinued mobilisation of sugar is a secondary phenomenon. Never- 

 theless, researches carried out during the last decade have led 

 to a belief on the part of many that neither inability, however 

 caused, of the liver to function in regulating the rise and fall 

 of glycogen, nor inability on the part of the tissues to utilise the 

 sugar brought to them, nor even a combination of these failures 

 will account for all the phenomena of diabetes, at any rate, as it 



