460 Mr. W. Stiles and Dr. F. Kidd. Position of the 



A-5 

 4 



1— t 



3-5 



O 



2-5 - 

 2 - 



2 2-5 3 3-5 4 4^5 S 



LOG E 



. Fig. 6.— The relation between final external and final internal concentration in the case 

 of carrot tissue immersed in certain chlorides. E is final external concentration and 

 I final internal concentration. 



It appears, in the first place, that the equilibrium reached in the absorp- 

 tion of a salt by living tissue depends upon the external concentration of the 

 salt absorbed. While the aisolute amount of absorption increases with 

 increasing concentration of salt in the external solution as far as our experi- 

 ments go, the amoimt relative to the external concentration nevertheless 

 decreases rapidly from the lowest concentrations upwards. 



Secondly, when the external concentrations of salt used are low, the 

 absorption ratios become greater than unity, and with very dilute solutions 

 probably rise to extraordinarily high values. For example, in the case of 

 N/500NaCl, the concentration of this salt inside the tissue after its absorp- 

 tion was 27 times as great as it was outside at the end of the experiment. 

 Moreover, as we have already emphasized, this value is a minimum value for 

 the equilibrium absorption ratio. A " heaping up " of salts is directly 

 observed. With dead tissue, on the other hand, the equilibrium condition 

 reached in absorption from similar solutions is one of approximately equal 

 distribution of salt between tissues and bathing fluid. 



As the concentration of the external solution is increased, the heaping up 

 of the salt inside the tissue at equilibrium is reduced. In the highest con- 

 centrations used, i.e., N/10, the degree of absorption required to produce 

 nearly equal distribution of the salt throughout the tissue and the bathing 

 fluid such as is characteristic in the case of dead tissue, is not reached. The 

 absorption ratio at equilibrium is less than unity. With calcium chloride N/10, 

 for example, where the absorption curve shows that equilibrium had been 

 practically attained by the end of the experiment, the concentration then 

 inside the tissue was still only about one quarter of that outside. 



