640 DIABETES 



E. ]\r. Wilder has been unable to confirm this observation. Woodyatt, 

 Sansum and Wilder ^ made continued intravenous injections of glu- 

 cose at uniform rates by means of a motor driven pump for 2 to 17 

 hours with the following- findings : 



If chemically pure glucose in aqueous solution is injected con- 

 tinuously into the peripheral venous blood of a normal resting man, 

 dog or rabbit at the rate of 0.8 gm. per kg. of body weight per hour, 

 or at any slower rate, the injection may be sustained in most cases, 

 hour after hour for 7 hours and probably longer without producing 

 any glycosuria in the usual sense of the word. If the rate is advanced 

 to 0.9 gm. of glucose per kg. of body weight per hour, while all other 

 conditions remain the same, the injection may be sustained for a short 

 time without causing glycosuria, but in nearly all cases abnormal 

 quantities of glucose beg^in to appear in the urine after 5 to 30 minutes 

 of injection, the time depending upon the previous degree of satura- 

 tion. Once established,- the glycosuria then tends to proceed at a 

 uniform rate as long as the rate of injection and other conditions re- 

 main fixed. However, if the injection rate is again reduced to 0.8 gm. 

 per kg., glycosuria promptly ceases. Thus during the continuance of 

 an injection at the latter (0.8 gm.) rate there can be no continued 

 accumulation of unchanged glucose in the body, but the rate of injec- 

 tion is equalled hy the rate of utilization. It is important to note 

 that it makes no appreciable difference whether one uses an 18 or a 

 72 per cent, glucose solution for injection. The tolerance limit for 

 glucose may be demonstrated at the same point regardless of wide 

 variation in the quantity of water administered with the glucose, even 

 1 hough the blood volume and the blood sugar percentages may be 

 influenced by variation of the water supply. Also, if glucose is in- 

 jected continuously and uniformly at a rate productive of some 

 glycosuria, the glucose excretion may proceed at a constant rate in 

 spite of marked variation in the water supply during successive hours. 

 A certain dog receiving by vein 20 gm. of glucose per 10 kg. per hour 

 for 8 hours, excreted every hour close to 0.42 gm. of sugar per 10 

 kg. of body weight. Yet during the experiment water was injected 

 at varying rates into the same vein with the glucose, so that the hourly 

 volume of urine varied between 6 c.c. and 128 c.c. and the percentages 

 of sugar in the ui'ine varied*betvveen 0.35 and 4.9. This em])hasizes 

 the fundamental importance of the rate at which sugar is supplied to 

 the organism in determining the occurrence or non-occurrence of 

 glycosuria and in fixing the rate of excretion when the latter occurs. 



In view of the above generalities several specific mechanisms sug- 

 gest themselves by which glycosuria might be produced : 



(1) An increased supply of preformed glucose to the whole organ- 

 ism from without (alimentary glycosuria). 



f Jour. Amor. M(>d. Assoc, 101.') ((>")). 2007 (preliminary report); Woodyatt, 

 ITarvev Sociptv Loftnros, IDIO; Wilder and Sansnm, Arch. Int. Med.. 1017 (10), 

 311; Woodyatt and Sansiun, Jour. Biol. Ciiem., 1017 (30), 155. 



