Walter Stiles 
248 
is no evidence from existing data that the presence of the sugar has 
any influence on the permeability of the cell membranes to water, 
nor is there any evidence of an appreciable entrance of the sugar 
nor of exosmosis of solutes from the cell sap. Similar results with 
potato in sucrose solutions were obtained by Thoday (1918 a). 
2. Sodium chloride 
Similar experiments with sodium chloride showed that this salt 
behaved to potato tissue in the same way as sucrose, but that the 
solution in which the tissue neither gained nor lost in weight possessed 
a concentration slightly higher than N/8. This lower concentration 
is to be expected from theoretical considerations as the ionisation of 
the sodium chloride in solution almost doubles its osmotic pressure. 
The absorption-time curves for the tissue in different concentrations 
of the salt are shown in Fig. 10. 
Similar experiments with carrot tissue showed that in a solution 
of N/3 concentration this tissue neither gained nor lost in weight. 
3. Ethyl alcohol, octyl alcohol, chloroform and 
MERCURIC CYANIDE 
The results obtained with ethyl alcohol were quite different from 
those with sucrose and sodium chloride. The results with potato 
tissue are shown graphically in Fig. 11. With lower concentrations 
(up to molecular) absorption at first takes place as in dilute solutions 
of sucrose. But it will be observed that if ethyl alcohol behaved 
similarly to sucrose, we should expect the potato to undergo neither 
gain nor loss in weight in a solution having a concentration of about 
M /4, whereas swelling even takes place initially in solutions having 
as high a concentration as 2 M. But in concentrations M and 2 M 
this swelling reaches a maximum, after which the solution loses 
water. With M/2 alcohol the maximum was not reached even after 
16 hours, but the swelling was lower than in distilled water; in M 
alcohol the maximum intake of water is reached in about 7 or 8 
hours, while in 2 M alcohol in about half an hour. With concentra¬ 
tions of alcohol higher than 2 M any preliminary period of water 
intake was not detected by the method, the excretion of water being 
rapid, the more so the higher the concentration of the external 
solution. The observation of Overton (1895) that ethyl alcohol may 
enter the cell so rapidly from hypertonic solutions that plasmolysis 
does not take place is in agreement with the behaviour noted here. 
