298 
RICHARD M. HOLMAN 
The radius of curvature in the case of root "B" was 64 cm. For 
more than forty hours the elongating zone of this root occupied 
positions from the horizontal to 35° below the horizontal and during 
this time the extreme tip was directed obliquely downward. In spite 
of the root tip, as well as the elongating zone, being for so long a time 
in an extra-perpendicular position, a condition presumably favorable 
to the induction of the supposed plagiotropic condition, the root, by 
Fig. 3. Tracings from photographs of roots of Vicia faba placed obHquely 
upward in moist loose sawdust in a Sachs's box. The first cross stroke from the 
right shows the position of the tip at the beginning of the observations. The other 
strokes show the positions of the tip after the following intervals: i — 24 hours, 
2 — 24 hours, 3 — 32 hours, 4 — 24 hours. 
a uniform curvature, attained a position only 5 degrees from the 
perpendicular in the subsequent forty-six hours. In the case of another 
root of the same series of four (see figure 3, C) after forty-eight hours 
growth amounting to 5 cm., the elongating region reached the hori- 
zontal. Nevertheless in the subsequent forty-eight hours the elon- 
3 
