594 Williams .— The Influence of Immersion in Certain 
and tested. Care was taken that all these sections were from leaves of as 
nearly as possible the same size and condition, in the same rosette of the 
plant. 
All experiments were carried on at the ordinary room temperature, 
and no corrections were possible for the effect this somewhat fluctuating 
temperature might have upon the permeability. 
Observations. 
If the rectangular cells were examined from time to time certain 
changes could be seen. The first thing to be noticed was the fact that the 
protoplasm, after short immersion in the electrolytic solution, shrunk away 
from the cell wall and formed threads and spherical masses. Treatment 
with pure water at these early stages was sufficient to restore the proto¬ 
plasm to its normal form, so that these changes were connected with 
osmotic changes. 
After a certain period of immersion in each case, when the sections 
were removed and treated with the ferric chloride, distinct blue coloration 
was seen in the plasmolysed masses of the protoplasm. Ceils examined at 
this stage of immersion without ferric chloride showed a very granular 
appearance in the protoplasm, this effect being especially marked in the 
experiments with barium chloride and nitrate. 
It was found that periods of immersion which allowed of blue tinting 
being obtained in the masses of protoplasm also served approximately to 
render the cell membrane permeable to the tannin within it, because a blue 
liquid was often seen also in the space between the shrunken protoplasm 
and the cell wall. 
Although permeability to both tannin and ferric chloride seemed to be 
produced by approximately the same periods of immersion, the membrane 
did not become permeable, at this stage, to the red material so frequently 
found in cells of tannin-bearing plants. In this particular plant the red 
pigment occurs in cells which do not actually contain the tannin, and is 
particularly abundant in early spring. This colouring matter is soluble in 
water, and passes out of the cell after longer periods in the electrolytes. 
It was frequent to obtain sections showing tracts of cells stained deep 
blue by the ‘tannin reaction, side by side with tracts showing a clear rose 
colour. A stronger iron solution than that used for the tests was able to 
combine with the rose pigment and produce a greenish-brown precipitate 
within the special cells. 
Results given below show details for five electrolytic solutions which 
were found capable of rendering the protoplasm permeable to the o -2 per 
cent, iron chloride. It is intended to carry out tests on a series of salts to 
find whether there is any general connexion between concentration and 
time of immersion necessary to produce the given change. 
