Action of Cheniicah on Potato-Ttthers. 273 



In the table Ijeneath are given the amounts of chlorides per 

 100 c.c. of brine solution at 5 and 6 days. 



Table 1. 

 Grams chlorides expressed as NaCl per 100 c.c. soln. 

 At commencement 

 After 5 days 

 After 6 days 

 . Percentage of salt 

 withdrawn from 

 100 c.c. of solu- 

 tion, after 5 days - 20.02 - 29.45 - 33.39 

 do. do. 6 days... - — - 33.24 - 33.89 



As these quantitative data show, a considerable amount of 

 salt passes by diffusion from the solution into the tissue of the 

 peeled tuber. Tlie titre of the external solution undergoes a 

 gradual fall. Tliis fall, probably rapid at first, gradually slows 

 down, until at about five or six days a condition of equilibrium 

 is attained. Tlie principal feature of these experiments to be 

 noted is the rapidity and order of magnitude of the process of 

 diffusion which occurs in the case of the peeled tuber, a 

 phenomenon which is, as we shall see, chiefiy caused by the 

 removal of the skin of the steeped object. 



The above results do not give an entirely accurate measure 

 of the passage of the solute from the solution into the tissue of the 

 tuber, for during the course of these and similar experiments, 

 evaporation of water occurs at the surface of the salt solution, 

 and this tends to concentrate it. The values given above (and 

 those in the succeeding tables) actually measure the resultant 

 of two opposed processes, diffusion of salt from the solution 

 into the tuber, and evaporation of water from the solution, 

 processes which respectively tend to diminish and increase 

 its concentration. 



These data, however, sufficiently demonstrate (under the 

 selected conditions of experiment), that common salt (NaCl) 

 very freely diffuses into and is absorbed by the tissue of peeled 

 tubers. 



Direct estimations of the chloride content of the tissue of 

 treated and untreated tubers definitely show that after treat- 



