RESPONSE OF ISOLATED VEGETAL NERVE 475 



modified to a still greater extent will show a purely abnormal 

 or positive electrical response. In the case of vegetable nerve, 

 I find exactly the same three types of response repeated, under 

 the same conditions. This will be seen in the three sets of 

 records given in fig. 285. The normal responses, which are 

 negative, are here represented as 'up,' while the abnormal 

 positive is represented as * down.' 



Still more remarkable is the parallelism observed between 

 the effects of tetanisation, on animal and vegetable nerve, 

 both normal and modified. In the case of fresh frog's 

 nerve the responses are, as we have seen, enhanced, after 



Fir,. 285. Photographic Record of Exhibition of Three Types of 

 Response, Normal Negative, Diphasic, and Abnormal Positive, in 

 Nerve of Fern under Different Conditions 



a period of tetanisation. The effect of tetanisation on 

 vegetable nerve is precisely similar, as is seen in fig. 286. 

 In the case of the modified frog's nerve, moreover, it is found 

 that the abnormal positive response tends, after tetanisation, 

 to become normal. This is seen in the abnormal response, 

 whether positive or diphasic, being converted to the normal 

 negative type. I have obtained exactly parallel effects in 

 the case of modified vegetable nerve. In fig. 287 we see 

 the abnormal diphasic response of vegetable nerve converted, 

 after tetanisation, into normal negative. 



Thus, as in the response of animal nerve, so also in that 

 of the vegetable, tetanisation is found to have the effect of 

 enhancing the normal, or converting the abnormal into 



