7 1 6 ThocLiy.—On the Effect of Chloroform on 
duces a reversible increase of the resistance of the living thallus of Laminaria 
to the passage of ions in an electric current ; whereas three times the con- 
centration of anaesthetic produces a brief reversible increase of resistance 
followed by a progressive decrease which is irreversible, and always ends 
in the thallus becoming as good a conductor as the sea-water itself, i. e. 
completely permeable. 
The increase of permeability shown by the exudation of fluid in leaves 
exposed to chloroform vapour has been recorded by Miss Irving and others, 
and already remarked on here ; it is especially obvious in leaves of Tropaeo - 
lum. Miss Irving 1 observed the exudation of water and flaccidity in Barley 
leaves, in experiments in which the respiration did not indicate fatal dis- 
organization, and it must still be held an open question whether a slight 
increase of permeability is always irreversible, as might be inferred from 
Osterhout’s experiments. According to Lepeschkin the increased exuda- 
tion of water which follows a moderate dose of chloroform, due to an 
increase of permeability, only lasts for a time when the chloroform is 
removed. 
In leaves the evidence seems to point to the possibility of recovery so 
long as visible disorganization has not begun, even though some increase of 
permeability has resulted. Whether the recovery is complete is, however, 
another question. There is evidence that starvation is hastened ; but this 
might be due merely to the depletion of reserves during stimulation. 
Muller-Thurgau and Schneider-Orelli 2 conclude, on the other hand, that 
etherized potatoes are prematurely aged, in the sense that the balance 
between starch formation and dissolution is altered in the same direction as 
during the normal ageing process which precedes sprouting, the concentration 
of sugar in the sap increasing. 
Another important question is the nature of the augmentation of the 
respiratory exchanges spoken of as stimulation. H. E. and E. F. Armstrong 
have shown that after drastic treatment with chloroform leaves of Cherry 
Laurel contain more sugar ; but this may be a degenerative change, due 
perhaps to hydrolysis of the glucoside, and associated with disorganization. 
It is true that where a distinct change in the respiratory quotient was 
observed in leaves of Cherry Laurel, it was an increase to approximately 
unity. On the other hand, the decrease in the respiratory quotient observed 
in leaves of Helianthus and Tropaeolum during stimulation suggests a tem- 
porary change in the nature of the respiratory material of quite a different 
kind. The data are not yet sufficiently numerous to allow of generalization. 
1 Loc. cit., p. 1079. 
2 Loc. cit., pp. 368-9. See also review in New Phytologist, ix, 1910, p. 337. 
