1915] LOEB—REGEN ERATION 255 
Figs. 6-10 give the average results of such experiments. The 
drawings were made May 10, seven days after the. operation. 
The isolated leaves (fig. 6) had all formed their adventitious roots, 
and so had some but not all the leaves with ‘“‘debudded” stems 
(fig. 7). The leaves which had lost only the upper bud had not 
formed roots as fast as the leaves with entirely ‘‘debudded” stems 
(fig.8). The leaves with normal stems (fig. 9) had not yet formed 
any adventitious roots, but the shoot (S) on the stem where the leaf 
had been removed had begun to grow out. 
The following record of an experiment performed May 1 had 
yielded on May 10 the following result: 
1. Completely isolated leaves (fig. 6). All ten leaves had 
formed adventitious roots and tiny shoots. 
2. Eighteen leaves each attached to a completely “debudded”’ 
stem (fig. 7). Eleven leaves had formed adventitious roots and 
one also adventitious shoots. 
. Ten leaves with a stem whose upper bud was removed 
(fig. 8). Four leaves had formed adventitious roots or shoots. 
4. Ten leaves with a normal stem (fig. 9). All these stems 
formed shoots from the upper bud. No leaf has formed adventi- 
tious roots or shoots. 
It is, therefore, obvious first that a stem whose buds are removed has 
still an inhibiting influence upon the formation of roots in the notches 
of a leaf; and second, that if the buds of the stem are not removed 
the growth of the bud opposite the leaf enhances this inhibiting effect of 
the stem upon the leaf considerably. 
Since the growth of this bud of the stem is as a rule also inhibited 
when the opposite leaf is not removed, as in fig. 3, we understand 
why the non-removal of this leaf favors the growth of the adventi- 
tious roots from the notches of the other leaf. 
We have seen that isolated leaves when suspended im moist air 
will form roots and shoots from their notches even if they are not 
submersed in water; while if a leaf is connected with a stem, the 
formation of roots and shoots in the notches will be permanently 
inhibited in moist air. It should be added, that the leaves attached 
to a “debudded” stem may form very short adventitious roots 
when suspended in moist air (instead of in water), but will not 
