194 COMPARATIVE ELECTRO-PHYSIOLOGY 



detection of some effect which at the moment of death under- 

 went a sudden reversal to its opposite. There would not 

 here be even that minor degree of uncertainty which is in- 

 cidental to the determination of the exact vanishing-point of 

 a waning effect. And such methods are afforded by my 

 discovery of the occurrence of mechanical and electrical 

 spasms at the moment of death. 



Turning now to the method of the waning effect, we have 

 seen that response to stimulus^by galvanometric negativity is 

 distinctive of the living condition. When the plant is killed, 

 this normal response disappears. At the moment of death 

 from high temperature, therefore, we may expect to see the 

 abolition of this normal excitatory response of negativity. 



For this investigation I took a batch of six radishes. 

 The specimens were kept for five minutes previous to each 

 experiment in water at a definite temperature (say of 17 C), 

 and were then mounted in the vibration-apparatus and 

 their responses observed. Each specimen was next dis- 

 mounted and replaced in the bath at a higher tempera- 

 ture (say of 30 C.) for another five minutes. After this, a 

 second set of responses, to the same stimulus as before, was 

 taken. In this way observations were made with each plant, 

 till the temperature at which response almost or altogether 

 ceased was reached. I give below (p. 195) a table of the 

 results obtained with the six radishes. 



From these experiments it would appear that in these 

 cases the responses disappeared at about 55 C. It should 

 be stated here that this investigation was carried out in the 

 winter season in England, and it will be shown later that 

 the incidence of cold has the effect of lowering the normal 

 death-point by about 4 or 5 C. 



I was next desirous of substituting, for this method of 

 discontinuous observations, one which should be continuous. 

 I, therefore, subjected the specimen a stem of Amaranth 

 to a continuous rise of temperature, and took records of 

 responses to uniform stimuli after every few degrees of the 

 ascent. I found here that not only was there a gradual 



