1915] LOEB—REGENERATION 275 
were cut out from the plant, deprived of their leaves, and put on 
moist soil. As is usual, shoots grew out very soon from the top 
buds of the stem; very soon after- 
ward the piece in front of the top 
node began to shrink and wilt, not 
directly to the top node, but to 
within a few millimeters (fig. 40). 
When by chance the new shoot 
grows out not from the top node 
but from the one next to it, the 
whole piece in front of the top 
node may wilt (fig. 41). 
These observations were made 
FIG. 37 
on stems kept in the laboratory rooms (not in the greenhouse). 
When the root of the stem is left intact and in its natural position, 
Fics. 38 AND 39 
this wilting of the piece of 
the stem in front of the 
node from which the new 
shoots grow out will not: 
occur. The ascending 
flow of liquid or material 
in the stem was deflected 
in this experiment into the 
most apical bud, and there 
was not enough root pres- 
sure to maintain a flow 
through the pieces of the 
old stem more apical than 
the new shoot. 
By way of parentheses 
we may here briefly men- 
tion that light exercises a 
great influence on the 
growth of the notches of 
an isolated leaf. If such 
leaves are suspended in moist air but free from light, as a rule 
none of the notches will grow out, while they will grow out 
