242 BOTANICAL GAZETTE [ocroBER 
deep as four-fifths through the stem, has no influence. String was 
tied tightly around young stems, just above the primordia, and as the 
stems grew the string cut in deeply on all sides; no results followed. 
Longitudinal slices, the length of the epicotyl and three-fourths through 
the stem, produced no results. 
Experiment 38.—Notches cut at different points in a spiral around 
the stem, so that all the bundles were severed, failed to incite the 
buds below. 
Experiment 39.—Five plants 70-100°™ high, 6-9 internodes long, 
and with lower internodes old and hard were used. The tip of each 
plant was cut off and also the buds from all the nodes below. In 
three plants the basal primordia produced shoots; one plant died; 
and the others remained alive, but no shoots formed. Here the 
wound effect, if there was such, traveled through a distance of nine 
internodes. A wound, however severe, seems unable to cause the 
buds to develop if it does not include the complete removal of the 
growing apex; and even on a large plant the removal of the very 
tip is all that is necessary. Here, as in the willow and other plants 
(see experiment 43), the effect of the wound passes only down the 
stem; a wounding or a complete severance at any point along the 
stem has no effect on the buds above this point. As will be brought 
out later, the opposite is true of the roots; that is, the influence of 
the removal in inciting new roots only passes upwards. This would 
hardly be true if it were due to the diffusion of substances formed 
in the wounded cells, as WIESNER supposes. GOEBEL (5) has 
found that in Bryophyllum no wounding at all is needed to produce 
shoots on the leaves. He encased all the buds on the shoot in plaster 
so as to prevent further growth, and after a time the buds on the 
leaves developed. If the leaf blade of Cyclamen is cut off new 
leafy structures arise along the margins of the petals. But WINKLER 
(19) has shown that this removal is not necessary. He left the blades 
intact, but incased them in plaster, and soon the leaf-like outgrow 
appeared as when the blade was removed. The blade was not 
injured or wounded in any way by this treatment, though undoubtedly 
some of its activities were suppressed. ”g , 
As will be described in experiment 4o, I inhibited the growth 
the apex of Phaseolus by placing it in a hydrogen atmosphere. ° * 
