METABOLISM OF CARBO-HYDRATES GLYCOSURI AS 543 



by a greater amount than in pancreatic diabetes, perhaps because 

 the diminished content of sugar in the blood constitutes a more 

 insistent call upon the proteins to produce sugar. In pancreatic 

 diabetes, where hyperglycaemia exists, there can at least be no 

 reason for the formation of sugar from protein for the maintenance 

 of the normal sugar-content of the blood, and it is interesting that 

 in this condition the giving of dextrose does not seem to spare any 

 protein (p. 595). The degree of intolerance for carbo-hydrates in 

 pathological diabetes may be arrived at by putting the patient on 

 a diet of protein and fat (rich cream, meat, butter, and eggs), and 

 determining the ratio of dextrose to nitrogen excreted. If it is 3.6 or 

 37: i, intolerance is complete, none of the dextrose produced from 

 protein being burned, and there will probably be a quickly fatal 

 issue (Lusk and Man del). 



f Glycosuria can be caused in many other ways than those already 

 mentioned. Sometimes the action seems to be a direct one on the 

 sugar-regulating centre e.g., in concussion of the brain, occlusion 

 and subsequent release of the arteries supplying the brain and 

 cervical cord, and acute haemorrhage.)/ Carbon monoxide has a 

 similar action owing to the deficiency of oxygen occasioned by it. 

 Many drugs also cause glycosuria, including curara, morphine, 

 strychnine, phosphorus, chloroform, ether, and other substances, 

 some of which may act on the ' sugar centre/ although others e.g., 

 phosphorus and chloroform are poisons which can affect the liver 

 directly. ) Injection of water or physiological salt solution into the 

 bile-ducts, or into the mesenteric veins, or of salt solution in consider- 

 able amount into the general circulation, is followed by glycosuria 

 (Fischer, etc.). 



f Diabetes Mellitus)-f-In the natural diabetes of man, as in all the 

 forms of glycosuria mentioned, with the exception of that produced 

 by phlorhizin, the immediate cause of the glycosuria is the increase 

 of sugar in the blood.) /Instead of the I part per i,oooj or a little 

 more or less, which constitutes the normal proportion in a healthy 

 man, [in diabetes 3 or 4 parts, and in exceptional cases even 7 to 

 10 parts per 1,000 may be present. ) The riddle of diabetes is the 

 explanation of this persistent nyperglycaemia. Innumerable 

 hypotheses have been framed to account for this, but on the whole 

 three possibilities have been emphasized :((i) That the power of 

 temporarily storing carbohydrates is deranged j[ (2) that the power 

 of the tissues to utilize carbo-hydrates (i.e., eventually dextrose) 

 is diminished or abolished Y(3) that too much sugar is produced in 

 the body.) In addition, some writers have postulated a fourth 

 factor to explain certain cases (of so-called ' renal diabetes ') to wit, 

 an increase in the permeability of the kidneys for sugar, as in 

 phlorhizin glycosuria. Lest the student should be bewildered 

 amongst all these theories, he should take note that there is every 



