( 428 ) 
finally appeared from the fact that in a small spot at the wound, 
exactly in the place where the currents from the prolification reached 
if, a number of small rootlets were formed. 
Hence the basipetal impulse was so strong that it entirely prevented 
a cross-communication, as a consequence of which each of the parts 
of the leaf formed two individuals, cohering in a morphological 
sense but scarcely in a physiological sense. 
We spoke above of currents that were reflected by the wound; 
this expression was chosen because the direction of the wound evidently 
influences the direction which the current assumes afterwards and 
this in a similar way in which a solid wall affects an impinging 
wave-front. 
This influence is most clearly seen when of three leaves the top 
part is cut off, (this latter being taken as large as possible) following 
in the first leaf a transverse line, in the second a V-shaped one, the 
point of the V bemg downward, and in the last leaf an inverted 
V-shaped line. After a few days the currents are seen to bend near 
the wound in such a way that the lines bisecting these current arches, 
are in the first case parallel to the longitudinal axis of the leaf, in 
the second converge and in the third diverge. These currents are 
often so strong that one can follow them over long distances with 
the naked eye. 
However, only those parts of the currents that lie near the wound 
must be taken into account, firstly because the reflection is not 
sudden but gradual, so that the currents assume a more or less sharp 
bend with a radius of '/, to 2 mm, secondly because the leaves are 
rather narrow and so the reflected currents cannot, for a long 
distance, freely continue their new course. 
That in the formation of wound-cork in higher plants the new 
cross-walls in the phellogen are always parallel to the direction of 
the wound in the nearest place, suggests a similar influence of the 
wound in these plants. 
The basipetal impulse, indicated by the experiments mentioned, 
shows itself no less distinetly in the formation of new organs in eut 
leaves. ') 
1) | never saw rootlets or rhizomes arise on intact leaves, attached to the rhi- 
zome; cut rootlets die off at once, while loose rhizomes, when they are strong 
enough, form new organs, but always in an entirely normal way. 
