Walter Stiles 
130 
Whether chemical action or absorption is mainly responsible for 
this result cannot at present be said definitely any more than it can 
be for the case of salts. 
A few observations are on record indicating that the rate of intake 
of dyes is increased by rise in temperature. Pfeffer (1886) found this 
the case with methylene blue and Endler (1912 b) for neutral red. 
Collander (1921) has recently made some observations on the in¬ 
fluence of temperature on the intake of some sulphonic acid dyes 
(orange G and cyanol), and concludes that temperature has a con¬ 
siderable effect on the intake of these dyes by the pith cells of Tro- 
pceolum. Similar results were obtained with the parenchyma cells of 
perianth leaves of Hyacinthus, although the temperature effect was not 
so great. As, however, the intake of dye was not followed with time, 
information relative to the temperature coefficient is not forthcoming. 
Influence of light on the rate of absorption. The influence of light 
on the rate of absorption of sodium chloride by palisade cells of Acer 
platanoides, Salix babylonica and Buxus sempervirens was examined 
by Trondle (1918 b) by the deplasmolytic method. The results 
indicate that increasing illumination increases the rate at which the 
salt passes into the cells up to a maximum with a certain light 
intensity. This intensity varies with the different cells examined; 
with Acer platanoides it was about 1250 metre candles, with Salix 
babylonica about 9375 metre candles and with Buxus sempervirens 
about 1500 metre candles. Results obtained previously by the same 
author (1910) by the method of permeability coefficients gave similar 
indications. On the other hand, Ruhland (1911), using this latter 
method, found that light was without measurable influence on the 
permeability of the cells of the sugar beet leaf to sucrose, glucose and 
fructose. 
Using this same method Lepeschkin (1909 b) showed that the 
cells of the pulvini were more rapidly penetrated by dissolved sub¬ 
stances after illumination than in the dark, an observation confirmed 
by Blackman and Paine (1918) by determining the exosmosis of 
electrolytes by means of changes in the electrical conductivity of the 
external liquid. For reasons already given, neither the method of 
permeability coefficients nor the deplasmolytic method can be regarded 
as capable of yielding exact quantitative data with regard to the 
passage of substances into the cell. However, a more rapid rate of 
deplasmolysis can probably be accepted as indicating more rapid 
entrance of dissolved substance, and a higher permeability coefficient 
as indicating the same thing. 
