266 BOTANICAL GAZETTE [OCTOBER 
The results of the final measurements and tests are shown by 
percentages. Assuming in reference to each measurement and test 
that too represents the value for. the control plants, we have for 
the experimental plants the following numbers: height at the begin- 
ning of the experiment 97.67, at the conclusion 92.33; diameter 
at the beginning 100.2, at the conclusion 104.5; resistance to 
bending 120.6; resistance to crushing 104.2. The slightly greater 
bending and crushing resistances were probably due to the some- 
what greater diameter of the experimental plants. 
Cross-sections of the stems in this series were prepared and 
studied with special reference to the hard bast fibers and the col- 
lenchyma. The number of hard bast fibers in each stem vee 
ascertained by counting. The average number for the expert 
mental plants was practically equal to the average for the control 
plants. In each stem the thickness of three collenchyma walls 
was measured by means of an eyepiece micrometer, and from these 
measurements the average width of the collenchyma walls deter- 
mined; there was found to be a difference of only 0.07 # between 
the two averages; moreover, this excess was on the side of the 
control plants. 
CASTOR OIL PLANT (GARDEN PLANTS) 
Eighteen castor oil plants were selected from a large number 
grown in the garden. These plants were tied to stakes and weighted 
in the usual manner. They were about 17 cm. in height and 9.5 ™™ 
in diameter at the beginning of the experiment; they increased 
about 75 per cent in height and 4o per cent in diameter during the 
experimental period of ten days. At the conclusion of the exper 
ment, the experimental plants were supporting 5-7 kilos each. 
The usual measurement and test showed no marked difference: 
Letting 100 represent the value for each control plant average, the 
following numbers represent the relative values for experimenta 
plant average: height at the beginning of the experiment 101. 3; 
at the conclusion 97.2; diameter at the beginning ro1.6, at the 
conclusion ror.4; resistance to bending ror.8, to crushing 107-5) 
amount of xylem tog. 3. ; 
Another experiment was conducted with 30 selected castot ail 
