642 DIA BETES 



globiu pereeiitajio remaiiiinp' iiiiehaiigod, jn-obably because the large 

 quantity of ghieose in the bowel held water there. But in the second 

 hour the blood volume became large and the hemoglobin showed the 

 effects of dilution. In this same hour the sugar percentage returned 

 to normal. But the absorption of glucose was only completed in the 

 fourth lumr and calorinietric observations by Lusk showed that the 

 metabolism also ran at a uniform rate 20 per cent, above the basal 

 level into the fourth hour. Accordingly the observed blood sugar per- 

 centages first rose as tlie rate of sugar supply was increased, but fell 

 again during the )i\ainte)iance of the increased siipphj and ichih the 

 metabolism was constant, owing to the shifting of water. 



When concentrated (54 to 72 per cent.) glucose solutions are in- 

 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 whicli 

 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 ])lood 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 cpiantitative 

 distribution of free sugar between tliese two fluids, and the ((uantity 

 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. 80 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 b\" 

 su])plying water with the sugar as fast as it flows away in the urine, 

 provided the rate of injection is not so great that tlie necessary traffic 

 in water overtaxes the cardio-i-enal mechanism. By employing these 

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

 levels as c(mipatil)le with life and recovery, it is possible to produce 

 and maintain for houi's blood sugar concenti'ations as higli as 2.;?8 ]K'r 

 cent. Joslin obsei-ved 1.40 ])er cent, of sugai' in llic blood of a fatal 

 case of diabetes with nephi'itis. This is ])rol)ably the highest on 

 record. Tlie blood sugai- of diabetics passing sugar in the ni'ine is as 



