Permeability 
247 
rate of exosmosis and the quantity of water exuded increasing with 
increase of sugar concentration. 
Since, as we have already noted, the rate of intake of water is 
proportional both to the permeability and to the net suction 
pressure, so that dw 
dt 
— t{P— Pe — T) A, 
Fig. 10. Curves illustrating the absorption of water by potato tuber immersed 
in distilled water ( D.W.) and sodium chloride solutions of various concen- 
/N N\ , 
trations ( — to — J. (After Stiles and Jprgensen.) 
and as with increase in the concentration of the sugar P e increases, 
and consequently P — P e — T decreases, the observed results can be 
explained on account of the reduction of the net suction pressure 
with increasing concentration of the external sugar solution; there 
