i 2 6 RESEARCHES ON IRRITABILITY OF PLANTS 



results that were invariably concordant. I content myself, 

 however, with giving two records in each case, obtained 

 from different specimens. In order to test still further the 

 reliability of these results I was careful, with each pair 

 of figures given for comparison, to employ two different 

 recorders, the vibration-frequency of the first being ioo, 

 and of the second or companion-set 50 per second. 



In fig. 75, with vibrating recorder of 100, are given 

 two records testing the effect of intensity of stimulus on 

 the latent period. The lower of the two was obtained 

 with the minimum stimulus of 1 ; and the latent period is 

 seen to be -155 second. In the upper of the two records we 



Figs. 75, 76. — Effect of intensity of stimulus on latent period : the 

 upper record in each is due to stronger stimulus. 



have the result of the maximal stimulus of 5. The latent 

 period is now found to be reduced to "i second. 



In fig. 76, with vibrating recorder of 50 and taking 

 a different specimen, we find a precisely similar result. 

 The lower of the two records, with the minimal stimulus 

 of 1, shows a latent period of -14 second. The upper, with 

 stimulus 2, which in this individual case was maximal, 

 shows a latent period of "09 second. 



It is interesting to note alike in figs. 75 and 76 the great 

 vigour of the responsive movement under higher intensity 

 of stimulus, as seen in the abruptness of the rise of the 

 curve and the wider spacing of the successive dots. 



