39i 
Bayliss. — On the Galvanotropism of Roots. 
Through one set of radicles growing in gelatine a very strong electric 
current (320 volts) was passed for a few minutes, and then the radicles were 
wiped and divided longitudinally at right angles to the direction of the 
current and pressed on to litmus-paper, but no trace of any internal dif- 
ferential polarization could be detected. Both halves of those radicles 
taken out of the strongly alkaline region contained local acid areas sur- 
rounded by alkaline ones : in the strongly acid region both halves were 
strongly acid, and an acid reaction similar to that of unstimulated roots was 
all that could be detected in the intermediately placed roots. 
4. Experiments with Polarizable Electrodes directly 
APPLIED TO THE ROOT. 
But more definite results were found by placing the electrodes directly 
on the roots. 
Strong currents were applied by means of tapering platinum electrodes 
touching appropriate points on the root, which was kept moist during 
the process. The voltage used in such cases was 4-2, but the current 
naturally depended mainly upon the variable resistance of the interposed 
tissues. 
After marking with Indian ink the side (not the place) which the 
Fig. 2. Diagram showing apparatus used when passing a weak constant current through a root. 
positive electrode had touched, the seedlings were pinned to a cork 
(perforated for aeration) which fitted into a small moist chamber lined with 
moist blotting-paper. This chamber was now attached to a clinostat and 
F f 2 
