294 
Maugham. — On the Mechanism of 
narcosis, and noted the effect of the treatment on the removal of starch from 
the leaves. He found that killed elements no longer permitted translocation 
to go on, but that unkilled plasmolysed (5 per cent. KN 0 3 ) cells behaved 
almost as normal ones. Narcosis prevented translocation, which, however, 
recommenced on recovery of the cells. 
Deleano 1 criticized particular features of this work, but the conclu- 
sion drawn by Czapek that translocation is dependent upon protoplasmic 
activity remains unshaken. 
In the paper referred to, Czapek appeared to consider that during 
translocation sugar is actively taken into the substance of the protoplasm, 
chemically combined with it, and then excreted again on the other side, 
where it is taken into the protoplasm of the next cell after diffusing through 
the intervening cell-wall. 2 The vacuole was regarded as a sort of reservoir 
of nutriment for the protoplasm. 
His views with regard to the role of connecting-threads are related 
to observations depending on a technique which has since been greatly 
improved upon. 
It is interesting to note that Czapek found that translocation occurred 
in isolated plant portions, provided that a sufficient length (e. g. 12 cm. in 
one experiment with Vitis) of conducting path remained in connexion with 
the leaf. 3 
Of recent years much work has been done aiming at elucidating the 
properties and finer structure of protoplasm. In particular, the outer 
bounding layer, of undefined thickness, generally known as the * plasmatic 
membrane \ has received attention at the hands of many investigators. 4 
The majority of these researches have been concerned closely with the 
determination of the permeability of this membrane to various solutes, with 
the relation of permeability to changes in external factors, with the antago- 
nistic action of some salts upon others, and with the effects of anaesthetics. 5 
Many valuable results have been obtained, and light has been thrown 
upon the structure of protoplasm and of the membrane in question. 
While at the present time the knowledge available is insufficient to 
permit, for example, of a satisfactory diagrammatic representation of the 
spatial distribution of the constituent particles of the membrane, yet it seems 
clear that the protoplasm as a whole forms a heterogeneous system, or 
colloidal complex, in which water, proteins, and lipoids are important 
components. 
As stated by the Gibbs-Thomson rule, in such a system substances 
which in any way are able to lower the energy of the surface will, if free to 
1 Deleano (1911). Cf. Schroeder (1911) for abstract and an estimate of the value of Deleano’s 
conclusions. 
2 Czapek, 1. c., p. 158. 3 Ibid., pp. 148-9. 4 Blackman (1912). 
6 Atkins (1 916) and Bayliss (1915). General accounts and bibliographies are given. 
