402 Bayliss. — On the Galvanotropism of Roots. 
An explanation of this may be found by supposing these curvatures to 
be due chiefly to the travelling ions, and since evidence points to the acid 
ions being the more effective, the impingement of these on the sides of the 
roots facing the — electrode would bring about a curvature in that direction. 
Another argument which might be put forward to account for this 
apparent peculiarity is that since roots are normally acid, they might, 
according to Weber’s Law, be more responsive to alkali at first, whereas 
when the acidity reached a certain intensity its primary greater stimulating 
action would come into play, and overcome the predominant influence 
excited by the first traces of alkali. Also roots growing in gelatine would, 
owing to poor aeration, have more C0 2 in their tissues, and hence might 
even be more acid than normal. 
The curvatures to the + and — electrodes in the immediate vicinity 
of these electrodes are without doubt due mainly to the direct action of the 
accumulated acid and alkali in these regions, the ions diffusing to the root 
in the opposite direction to that in which they are carried by the electric 
current. 
To test how far a curvature was due to the action of an accumulation 
of ions or to the impingement of travelling ions when the electrodes were 
directly applied, a few experiments were made, using chloroform to render 
the protoplasm non-irritable during the time the ions would be travelling 
through it. At first a saturated solution of chloroform in distilled water 
was used : the effect of the chloroform lasted so long that no curve was 
visible within twenty-four hours of stimulation ; but a half-saturated 
solution answered well. 
The roots were placed in the liquid for four minutes, stimulated for 
four minutes, then washed, and after seventeen hours they were compared 
with a control set, stimulated but not chloroformed. The chloroformed 
ones curved to a greater extent, and showed more vigorous growth, hence 
a conclusion might be drawn that this was due to the antagonistic action 
of the travelling ions being eliminated owing to the non-irritable condition 
of the roots during the passage of the current, and only the action of the 
accumulated ions allowed to be effective, since this action comes into play 
as the effect of the chloroform passes away. An electric current was passed 
through a dilute salt solution saturated with chloroform, and it was found 
that the chloroform did not appreciably effect the conductivity of the 
liquid, so that the presence of chloroform in the root does not alter its 
conductivity, and hence allow more or less current to pass than through 
unchloroformed roots. Also some seedlings were chloroformed as above, 
and laid horizontally, and their feeble curvatures after seventeen hours 
showed that the chloroform had lowered their geotropic irritability 
considerably. 
The above results show that, although Brunchhorst’s facts are correct 
