472 
.T. GRAY. 
relation ol the cell to electrolytes is of prime importance to 
its existence. 
The work of McClendon (13) and R. S. Lillie (9-11) has 
shown that, after fertilisation, the egg surface is more per- 
meable to ions than before. It has also been demonstrated 
that the CO 2 production of a dividing cell, changes just 
before each division, i. e. there is a slight increase in perme- 
ability.^ It is also highly probable that the effect of hyper- 
tonic solution upon a cell is to decrease its permeability to 
ions (Sutherland [16], Lillie). 
The whole of the evidence in favour of the view that the 
permeability changes of the egg membranes (plasmic and 
nuclear) are of profound importance to the activities of the 
cell cannot be discussed in full, but the following extract 
from a recent paper .by^ R. S. Lillie (11) has a peculiar inte- 
rest in connection with the phenomena discussed in this 
paper : 
‘•'The conclusion that many pathological conditions have 
their primary origin in abnormalities of the limiting mem- 
branes of cells is an obvious corollary of any view that 
regards such membranes — which are essentially insulating 
surface films of varying ionic permeability and electrical 
polarisation — as largely controlling the rate and character 
of the cell processes. If stimulation depends primarily upon 
altered polarisation of the plasma-membrane due to increased 
ionic permeability, it is clear that a normal response in the 
case of any cell, implies a definite condition of the membrane. 
If this condition is permanently altered, the cell processes 
inevitably underg'o derangement, and pathological changes 
follow. Such a deranged condition, if not too far advanced, 
may be rectified by restoring the membrane to its normal 
condition. . . . The alteration caused by a toxic agent 
may consist primarily either in increasing or in decreasing 
the permeability normal to the membrane, or in altering in 
either direction the readiness with which the latter undergoes 
‘ The susceptibility of a dividing cell to poisons has also been shown 
to be rhythmical in the same way. 
