242 
LOCK : THE GROWTH OF 
Table XI V.—contd. 
The curves agree in their general features with those last 
described. Both culms were growing more rapidly by this 
time, and the variations in rate of growth are also somewhat 
greater. There was also considerable variation in the 
conditions and the table shows that a fair degree of parallel¬ 
ism could still be traced. 
At first sight it might appear that we have here a marked 
example of the influence of light upon growth. But there 
are several reasons which forbid this conclusion. In the 
first place conditions other than illumination are qnite 
uncontrolled. Moreover the changes in rate of growth are 
much greater than any which have hitherto been shown to 
depend upon the stimulus of changed illumination. Further, 
the culms do not appear to be at all heliotropic, and it is 
indeed hard to imagine how light can greatly affect the 
growing region through its thick and opaque armour of 
leaf sheaths. 
