_ Igog] BORDNER—INFLUENCE OF TRACTION ON STEMS 265 
cation among the controls. Stems 5, 7, 12, and 1 5 were all well 
lignified. The hard bast in approximately ro per cent. of the experi- 
mental stems was completely lignified. In the five stems for which 
the hard bast determinations were made, only a few elements were 
lignified in 8 and g, while in 16 lignification of the hard bast was 
almost complete. 
Experiment 5. Phaseolus vulgaris, greenhouse culture.—The 
plants for this experiment were grown and selected in a like manner 
to those for experiment 1. The tension fastening was placed just 
below the second pair of leaves. The experiment began October 21 
and ended November 8, 1907. The weight attached to the experi- 
mental plants, 400%™ at the beginning, was increased to g50%™ after 
five days, and to 11 50%" November 5. The controls were left 
unsupported. 
TABLE V.—Phaseolus vulgaris 
| a 4 : 
| Height to Diam. just iam. ge er 2 : z E 
No, of Height in 2d pair of above above coty- =; Se |& 5 M, ~ g2 
Plant cm. leaves in ground in ledons in os | Seale a Bax 
cm, mm. mm. ga | Suz] FX) 38 
AY a) rs) 4 
Oct. | Nov. | Oct. | Nov. | Oct. | Nov. | Oct. | Nov. | Nov. | Nov. | Nov. Br te 
Exp. 21 8 21 aI 2r 8 8 8 4 
(5 13.5 |25-. fEQ.E |a4ct [ds gala, Bap Sed fe wee 6.795|88.08) 6.59 
Control 
BV nas 13.3 {20.8 |12.0 |12.8 | 4.16] 4.53] 2.98] 3.34|-.--- 5.098|76.57| 5-42 
The average measurements and results of this experiment are 
given in table V. The breaking strength shows an increase in the 
€xperimental plants over the controls of 1.7**, or 33 percent. Sec- 
tions taken just below the breaks showed an increase of 15 per cent. 
in the area of hard bast, and 22 per cent. in the area of the xylem. 
hese measurements were made by method 3. The hard bast and 
xylem were equally lignified in experimental and control plants. 
Experiment 6. Phaseolus vulgaris, greenhouse culture.—These 
Plants, when the experiment was started, were ten days older than 
those used in experiment 5. The experiment began December 7, 
‘997, and ended January 7, 1908, at which date most of the blossoms 
had already fallen from the plants and the leaves were beginning 
lose their chlorophyll. A weight of 250%™ attached to the experi- 
