GOEBEL: REGENERATION IN PLANTS 199 
tion. Investigation showed that this development may be induced 
by cutting the larger vascular bundles, and also the veins of the 
leaf. The leaf remains fresh and attached to the plant, but be- 
comes covered with young sprouts through the growth of the 
rudiments on the edge of the leaf. We see by this that a discon- 
nection, or interruption of the conducting system gives the stim- 
ulus for the further development of the resting vegetative point 
on the leaf; but why this interruption should act as a stimulus 
has not yet been explained. Further investigations may throw 
some light upon this point. The vegetative points were removed 
from a number of plants except those found on the margins of the 
leaves. The result of this operation was that the vegetative 
points which usually remain dormant became active. The con- 
ductive system was not broken but the goal of the system was re- 
moved in a manner. For the vegetative points are to be consid- 
ered as centers of attraction for the constructive material which is 
carried thither to be used in the building up of new organs. We 
can say, therefore, that the presence of the vegetative points on 
the shoot prevents the development of those on the leaves. The 
former lay claim to the conducting channels that run through the 
leaf, and only when these are broken or the vegetative point of the 
shoot is removed do those on the leaves develop. A correlation 
is clearly apparent. 
Whether we have to do in this case with a quantitative relation 
to constructive material, as was assumed above for the sake of 
simplicity, or with imperfectly understood specific reactions to 
stimuli along the conducting system must for the present remain 
unsettled. 
It appeared of interest to me to determine the behavior of 
plants that have no vegetative points on the leaves, but possess 
only the tendency to construct adventitious shoots from cells 
which have passed over into permanent condition. The best 
known example of this is Begonia Rex. Florists propagate this 
plant by setting leaves cut from the stems in damp sand. At the 
base of the blade adventitious shoots appear; and one can easily 
induce them to appear on other places by cutting the larger veins 
of the leaf. 
If the above proposition is correct, it would necessarily follow 
