72 RESPONSE IN THE LIVING AND NON-LIVING 



of response. The immediate changes made in the 

 response, in consequence of the application of chemical 

 reagents, could then be demonstrated in a striking 

 manner. And with a little trouble, specimens can be 

 secured in which perfect regularity of response is found. 

 The record given in fig. 16, obtained with a specimen 

 of radish, shows how possible it is to secure plants in 

 which response is absolutely regular. I subjected this 

 to uniform stimulation at intervals of one minute, dur- 

 ing half an hour, without detecting the least variation 



Before ^ After 

 FIG. 43. EFFECT OF CHLOROFORM ON NERVE KESPONSE (WALLER) 



in the responses. But it is of course easier to find 

 others in which the responses as a whole may be taken 

 as regular, though there may be slight rhythmic 

 fluctuations. And even in these cases the effect of 

 reagents is too marked and sudden to escape notice. 



For the obtaining of constant and strong response I 

 found the best materials to be carrot and radish, selected 

 individuals from which gave most satisfactory results. 

 The carrots were at their best in August and September, 



