20 SCIENCE PROGRESS 



dextrose per kilogramme of body-weight could be injected in the 

 course of fifty-five minutes without any trace of glycosuria being 

 noticeable. If we may transfer such figures to the case of a 

 man of average weight (70 kilos.) they mean that more than 

 150 grammes of sugar per hour or 3,600 grammes a day, at 

 least seven times the normal consumption of carbohydrate, 

 might enter the circulation without appearing in the urine. 

 To say the truth, such figures are startling and require further 

 investigation to explain them. It is hardly likely that they can 

 be legitimately applied to human physiology but they leave, 

 at any rate, a large margin of evidence on which to base our 

 belief that hepatic sugar may enter the circulation normally 

 in quantities sufficient to supply the maximum demands of the 

 tissues without inducing glycosuria as a necessary consequence. 

 How far Pavy would have adjusted his teaching to meet these 

 results, which were only published after his death, we cannot 

 tell ; as all his writings show how great was the importance he 

 attached to an argument which his very last experiments were to 

 undermine, the circumstances are not without a degree of pathos. 



Pavy's own Hypothesis Concerning Assimilation : the 

 Lymphocytes as Carriers of the Food 



To return to the discussion of his published views. If 

 the glycogenic hypothesis be wrong and sugar be not transported 

 from liver to tissues, if therefore the glycogen found in the 

 former be not a store of carbohydrate to be drawn upon by 

 the latter, what is the significance of its appearance after carbo- 

 hydrate has been consumed ? Being an insoluble, non-diffusible 

 form of carbohydrate, the formation of glycogen provides the 

 chemical mechanism for trapping the intestinal sugar which 

 must be prevented from entering the general circulation. 

 When, according to Pavy's earliest teaching, it disappears from 

 the liver, it undergoes constructive, not destructive, changes. 

 That sugar can be converted into fat in the body is a physio- 

 logical certitude and Pavy's original conception was that the 

 formation of glycogen was essentially the first step on the 

 way to such conversion. He was prepared, however, to believe 

 that some other assimilative path might be- open to it ; what he 

 felt to be certain was that it was never again broken down into 

 sugar. As his views developed they became more definite with 



