670 



OJö'/g and glucose 0.17o '*^oine of the results are given in Table II. 



It becomes evident that if from the RiNGER-fluid containing the 

 right CaCl^. 6 aq. concentration viz. 0.0157o (see Table I) all the 

 potassium is omitted, glucose is still retained viz. ± 0.02°/, ; if the 

 KOI is increased to 0.005—0.006"/,, all the glucose passes through; 

 at a further increase to KCU 0.008 — O.Ol7"/o the maximum amount 

 of glucose is retained (0.037o) ; at higher KCl concentrations the 

 retention decreases again. 



Hence ice see that the /wtassiuryi is not absolutely necessary ^) ; the 

 chief function of the K in the transmission-tluid is probably to 

 balance an excess of Ca. 



It appeared from out last paper that the NaCl concentration also 

 affects the results. 



The composition of the transmission-fluid thus found could, however, 

 be hardly looked upon as the optimum one sijice from a trans mission- 

 fiuid lüith 0,1 7o of glucose at most only 0,037o ""?•>' retained. And 

 this value decreased even when the glucose-concentration in the 

 transmission-fluid was lowered. The reason why also experiments 

 with glucose-concentrations below 0.1 7o were made was due to the 

 fact that the normal glucose-concentration of frog's blood varies between 

 0,03 and 0,067„. If we used a glucose-concentration of 0,03— 0,047„ 

 not 0,03° was retained but at most 0,01 57o- The glucose retention 

 was, consequently, dependent on the glucose-concentration of the Irans- 

 raission-fluid ; a decrease in the glucose-concentration causes a 

 corresponding decrease in the retention. In spite of a great number 

 of experiments, we did not succeed in obtaining a glomerulus-flltrate 

 which contained no glucose. But even if the transmission-fluid 

 contained 0. T/, of glucose and moreover the abovementioned 

 favourable Ca- and K-concentrations were used, it not unfrequently 

 occurred, more especially in summer when the frog's have less 

 vitality, that little or no glucose was retained. Probably the most 

 effective composition of the Ringer-fluid had, therefore, not been 

 arrived at. 



Increase of the usual NaHCO ^-concentration. 



We, therefore, attempted to improve upon our transmission-fluid. 



1) The fact that it is necessary in the transmission-fluid for the heart need not 

 surprise us, because the heart uses potassium in its muscular labour ; things are 

 different for the kidney, which is mainly a passive though complicated and sensitive 

 living filler. Besides, the same arterial blood must supply ail organs and provide 

 every one with what it needs. Thus it may be understood that the most effective 

 artificial transmission iluid need not have the same composition for every separate 

 organ. 



