650 DIABETES 



jected continuously into the blood at rates of 0.4 to 0.8 gm. per kg. 

 per hour, there is at first a steep rise of the blood sugar percentage, 

 followed by a fall coincident with an increased hydremia, after which 

 a new equilibrium is established and the blood sugar percentage may 

 become constant at a "normal" level exactly as in the above. By 

 injecting glucose at the same rates in sufficiently dilute solutions this 

 initial rise may be very much reduced and the blood sugar percentage 

 established in later hours may even be lower than that observed before 

 injection began. On the other hand, if glucose is injected at rates 

 above 0.9 gm. per kg. per hour, glycosuria begins, and if the rate of 

 injection is rapid enough may be made intense. As glucose passes 

 through the kidney membrane, water tends to accumulate with the 

 glucose on the urinary side of the membrane (increased diuresis, 

 polyuria) . In the same way that glucose in the bowel lumen may tend 

 to withhold water from the blood, so a sufficient quantity of glucose 

 in the urinary tubules may manifest the same tendency in this local- 

 ity. Whether the glucose in the urinary tubules will have the effect 

 of concentrating the blood or vice versa will depend on the quantitative 

 distribution of free sugar between these two fluids, and the quantity 

 of water available for distribution between the blood sugar and the 

 urinary sugar. During continuous intravenous injections of glucose 

 at rates from 2.7 gm. per kg. per hour upward, 30 to 40 per cent, 

 of the glucose injected may be excreted and there is a strong tendency 

 toward dehydration of the whole body. This may be neutralized by 

 supplying water with the sugar as fast as it flows away in the urine, 

 provided the rate of injection is not so great that the necessarj^ traffic 

 in water overtaxes the cardio-renal mechanism. By employing these 

 high rates of injections and maintaining the water balance at as low 

 levels as compatible with life and recovery, it is possible to produce 

 and maintain for hours blood sugar concentrations as high as 2.38 per 

 cent. Joslin observed 1.49 per cent, of sugar in the blood of a fatal 

 case of diabetes with nephritis. The blood sugar of diabetics passing 

 sugar in the urine is as a rule higher than normal, but not necessarily 

 so, much depending on the water balance. Joslin's statistics show a 

 range of 0.07 to 0.43 per cent. 



THE STATE OF THE SUGAR IN THE BLOOD 



It has long been .believed that the sugar circulating in the blood 

 exists in two physical states, a diffusible and a non-diffusible, i. e., 

 as (a) Free glucose in a state comparable to that of glucose dissolved in 

 water, sucr6 actuelle of Lupine, (b) Sugar in a colloid state, sucre 

 virtuelle, Lupine. By the former term a very specific idea is conveyed. 

 One might think for instance of single molecules or clusters of two or 

 three, each holding in its sphere of influence a certain number of water 

 molecules like suns in solar sj'stems. Sucli sniall masses move at 

 high velocities, "diffuse" readily and create high "osmotic pressures." 



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