554 



That galactose is retained is efficient in llie same way as is tiie 

 case with glucose. While glucose is a source of energy for muscniar 

 contraction; tjalactone kdps hi the foniiatioii of the cerehrosldes. 



As has been remarked earlier, frogs of1en present not inconside- 

 rable ditrerences in their capacity for retaining gincose. The time 

 of year also has some inllnence. Therefore experiments were again 

 made with frogs that had lived nnder the same cirenmstances as 

 those of the experiments described above. 



Experiment 21 (Aug. i24). 



The perfusion liquid contains 0,r'/„ glucose. 



Reduction 0,1 c.c. of perfusion liquid O.iOO',. 



0,1 CO urine of right kidney 0,24 c.c. Iodine solution; redui:;tion 0,03%. 



0,1 c.c. urine of left kidney: 0,"22 c.c. Iodine solution; reduction 0,025"/,,. 



Retained by right kidney: 0.10-0,03 = 0,070/o. 



Retained by left kidney: 0,10-0 025 = 0,075% 



Experiment 22 (Aug. 24). 



The same perfusion liquid as in experiment 21. 



0,1 c.c. urine of right kidney: 0,25 c.c. Iodine solution; reduction 0,03250/o 



0,1 c.c. urine of left kidney : 0,22 c.c. Iodine solution ; reduction 0,025%,. 



Retained by right kidney : 0,10-0,0325 = 0,0675 /o- 



Retained by left kidney : 0,10-0,025 = 0,075 /,. 



It is clear thai I hose frogs, which were placed in the same cir- 

 cumstances as those of expei-iments 16 — 20, retained a innr.h larger 

 qwmtity of glucose than of galactose. 



It now seemed desirable to investigate whether the retention of 

 galactose although this occurred in a much smaller degree than 

 was the case with glucose, was governed by the same conditions 

 as regards the composition of the Ringer-solution, as had formerly 

 been found to apply to glucose. P'or this reason the following 

 Ringer's solution was used: NaCI 0,7 7„, NaHCO, 0,02 Vo. KCl 

 0.01 "/„ CaCI, 0.0075 V,. With the application of this solution 

 glucose was at the time retained to a maximum of 0.03 Vo- Only 

 when the quantity of NaHCO., was increased above 0.09 '/o on 

 account of which the urine was no longer acid, there could be retained 

 much more sugar; the urine could then even be free from sugar. 

 What mould no>v be the result with galactose if the Ringer's solu- 

 tion also in this case contained 0,02 7o NaHCOt only? 



Experiment 23 (Sept. 14). 



The perfusion liquid with only 0,02%, NaHCOj contains 0,P/,) galactose. 



Reduction of 0,1 c.c. of perfusion liquid 0.08"/,,. 



0,1 cc. urine of right kidney: 0,42 c.c. Iodine solution; reduction 0,075'^/(). 



0,1 c.c. urine of left kidney: 0,43 cc. Iodine solution; reduction 0,07750/(;. 



Retained by right kidney: 0,08-0,075=0,005%. 



Retained by left kidney : 0,08—0,0775 = 0,00257o. 



