THE AUTOMATIC RECORD OF GROWTH 155 



tracings in which growth appears as practically uniform ; 

 but such may be due to the resultant of the growth-pulses 

 at different levels and in different layers of tissue. Another 

 2xample of the extreme sensitiveness of the apparatus is 



FIG. 17. The High Magnification Crescograph. P, 

 plant ; C, clockwork for periodic oscillation of re- 

 cording smoked glass plate (G) ; S S', micrometer 

 screws ; K, crank ; R, eccentric ; W, rotating wheel. 



seen from the fact that it even detects the retardation of 

 growth caused by a mere touch, while a more violent 

 irritation arrests growth altogether. Though rough hand- 

 ling is harmful to a vigorous plant, Bose found that its 

 effect was, however, beneficial to a plant which had 

 remained backward in its growth. Corporal punishment 

 has therefore its uses ! 



