DIVERSE COMPONENTS 



339 



glucose. Possibly the curves would lose their convexity if the per- 

 sisting action were discounted. 



Taken together, figures 166, A, and 170, A, constitute a diagram 

 of net equilibration. But the scales of the latter figure must be 

 reduced to one-twentieth their present size in order to match those 

 of the former figure. The slopes near zero load are about equal in 

 the two curves, meaning that small excesses and small deficits are 

 adjusted with equal speeds. Only, the range of deficits that is 

 tolerated (and chemically possible) is very small compared with 

 the range of excesses. 



0.4 



-'03 -OZ -0.1 



Mean Glucose Load 

 Fig. 170. Kate of net glucose gain (gm./kg. hr.) in relation to mean glucose load 

 (gm./kg.), as found in the blood of dogs previously subjected to intravenous injections 

 of insulin, A and A', 17 and 12 tests with 0.1 unit insulin/kg- B, 5 and 8 tests with 

 0.5 unit/kg. C, 11 and 15 tests with 1.0 unit/kg. Solid points, bilaterally medullecto- 

 mized; open points, unoperated. Data of Zucker and Berg ('37, p. 541). 



If total exchanges of glucose were estimated instead of net 

 exchanges, the ordinate at zero load would be increased by 0.25 

 gm./kg. hr. It is unknown how total glucose gain varies in positive 

 loads, and total loss varies in negative loads. Whereas water, heat, 

 nitrogen, and carbon are probably lost only by modifications of 

 their rates of elimination from the dog's body, the specific com- 

 ponent glucose is disposed of by chemical transformation, a process 

 which also makes its total loss difficult to measure. Similarly, in 

 deficits the rates of net glucose gain reported might barely result 

 from diminutions of total loss without any increases of total gain. 



Had the hlood been chosen for study in place of the whole body, 



