994 
| %o of CaCl, 0/, of Reduction 
| of NaCl | %ofNaHCOs | %yof KCI | an ection | -———__— 
| “ water) Circul. fl. Urine 
Dsl <07 0.02 0.01 0.005 0.09 0.09 
2) 0.7 0.02 0.01 | 0.0075 0.095 | 0.065 
3) 0.7 0.02 0.01 0.010 0.09 0.08 
4) 0.7 0.02 0.01 0.015 0.09 0.09 
0,03°/, of glucose is retained. If the Ca-perc. is raised to 0,010 °/, 
only 0,01 °/, is retained, at 0,015 °/, nothing again. 
Hence the most favourable proportion between the concentrations 
of KCl and CaCl, is 4:3, which, expressed in the number of atoms, 
results in: K:Ca=2:1. The following table demonstrates that the 
proportion between K and Ca and not the absolute amount of Ca 
is the important thing, because a slight increase of the K-perc. 
necessitates a corresponding increase of Ca. 
| | | 9 Reduction 
Oo NaCl | % NaHCO, |! %KCI | % CaCl 
| Circul. fl. Urine 
0.7 0.02 0.01 0.0015 | 0,09 | 0.065 
Dts Ai 002 0.015 0.005 | 0.08 0.08 
07 Woe 0202 0.014 0.011 | 0.10 0.065 
It should be noticed that the glucose perc. in the blood of the 
winter-frog (these were used for the experiments) amounts to 0.03 °/,. 
In the summer-frog it is 0.05 °/). . 
In accordance with this difference it was found that the kidneys 
of the summer-frog, when treated with Rieer-fluid containing glucose, 
retained 0.05 °/, glucose, which is partly due to the temperature. 
We shall have occasion to mention the influence of the 
temperature again. 
5. The proportion of Na. K, Ca. 
4 Series of Experiments. 
In order to continue the experiments a new consignment of frogs 
had to be used. The RrNeer-fluid, used for circulation, consisted 
again of NaCl 0.7 °/,, NaHCO, 0.02 °/,, KCl 0.01 °/,, CaCl, 0.075 °/,, 
