256 BOTANICAL GAZETTE [OCTOBER 
no influence on the development of mechanical tissue. The dis- 
placement of orthotropic flower shoots to a plagiotropic position, 
he claimed, caused a certain anatomical change. This he attributed 
to the change in position and not to tension. His conclusion does 
not agree with those of other investigators, viz., that mechanical 
development of the fruit stalk goes hand in hand with the develop- 
ment of the fruit. : 
Methods 
In both greenhouse and field culture a much larger number of 
plants were grown than were used in each experiment. At the begin- 
ning of each experiment the strongest plants and those most nearly 
equal in size were selected, and the others were removed. This was 
done to reduce the chances, as far as possible, of individual variation. 
In the greenhouse cultures, the pots with the plants were placed in 
a row. The plants were then measured and every other one was 
taken as a control. At the close of the experiment, an average Was 
taken of all the data on the control, and also the experimental plants 
in each series. This was the method used by Scuortz. By pre 
liminary experiments, the writer was convinced that it was by far 
the most satisfactory, on account of individual variations in plants 
which make it very difficult to select any one plant that will be a fair 
control throughout the experiment for any one experimental plant. 
The methods of Batt and Hreparp for applying tension by pull 
in the direction of the longitudinal axis of the stem were followed. 
The writer was soon convinced, however, that for plants as large 
as those used in his experiments, the leather noose used by BALL # 
a tension fastening was not needed. Heavy cotton flannel and ordi- 
nary cotton cord, therefore, were used for this purpose in all these 
experiments. A strip of heavy cotton flannel 2.5°™ wide was wrapped 
at least twice around the stem. Over this, two cords were P@5* 
from opposite sides and back again. Each cord, thus passing twice 
around the stem, was drawn tight enough to keep the fastening from 
slipping. The ends of each cord were then tied to a second. 
were united into one strand some distance above the fastening. : av 
double cord was passed over a light running pulley, supported direc 
above the plant, and a weight was attached to its free end. At 
