REVIEW OF RESPONSE OF ANISOTROPIC ORGANS 717 



expiration of nearly three-quarters of an hour that the first sign 

 of apogeotropic action appears. This anomaly is probably due 

 to the induced mechanical curvature caused by weight which 

 has first to be overcome. We may, however, regard ourselves 

 as independent of the mechanical indications, when recording 

 the effect of gravitational stimulus by geo-electric response. 

 The excitatory electric effect, as we have seen in other cases, 

 takes place as before, when all responsive mechanical 

 indications are restrained. Proceeding on this principle, 

 therefore, I found that the geo-electric response was initiated 

 within so short a time of subjecting the specimen to gravi- 

 tational stimulus as one minute (fig. 271). This experiment 

 shows of what widespread application is the electrical mode 

 of detecting the excitatory response of tissues, to many 

 different forms of stimulus. 



