CHAPTER XIV 



CURRENT OF DEATH RESPONSE BY POSITIVE VARIATION 



Anomalous case of response by positive variation Inquiry into the cause 

 Electric exploration of dying and dead tissue : death being natural Determi- 

 nation of electric distribution in tissue with one end killed Dying tissue 

 shows maximum negativity, and dead tissue, positivity to living Explanation 

 of this peculiar distribution Response by negative or positive variation, 

 depending on degree of injury Three typical cases Explanation by theory of 

 assimilation and dissimilation misleading- All response finally traceable to 

 simple fundamental reactions. 



WE have seen in the last chapter that, in order to obtain 

 response by negative variation, it is customary among 

 investigators on animal physiology to kill one end of the 

 experimental tissue, say by scalding. It is generally sup- 

 posed also that dead tissue is negative to living. On stimu- 

 lation, the induced negativity of the living contact, now 

 superposed on the existing P.D. of the unilaterally killed 

 tissue, causes a negative variation of it. This mode of investi- 

 gation, by means of the negative variation, is one which has 

 hitherto, as we have seen, been universally regarded as reliable. 

 In the course of my investigations on the response of 

 vegetable tissues, by this mode of negative variation, however, 

 I have sometimes found response to take place by the positive 

 variation. Taking, for example, a stem of Balsam, I killed 

 one end by immersion in boiling water. On now subjecting 

 this to diffuse vibrational stimulus, the responsive action was 

 found to induce a positive variation of the existing current. 

 On further investigation, I found that the excitatory electrical 

 variation at the living contact had remained normal ; that is 

 to say, the direction of the responsive current was away 

 from the excited living, and towards the killed end. I next 



