THE DEATII-SPASM IN PLANTS I49 



consist in watching the waning of a given effect, characteristic 

 of the living condition. Still better would be the discovery 

 of some effect suddenly and strikingly manifested at death. 

 But the ideal method would be found, if some effect could be 

 detected which at the moment of death would undergo 

 sudden reversal to its opposite. In this last case, there 

 would not be even that minor degree of imcertainty which is 

 incidental to the determination of the exact vanishing-point 

 of a waning effect. I have been successful in devising four 

 distinct means, by which the death-point might be detected 

 with precision, and it will be shown that all these different 

 modes of investigation enable results to be obtained which 

 corroborate each other in a remarkable manner. The four 

 means are : (a) the method of electrical response ; (d) that 

 method by which the point of death is determined from the 

 occurrence of a spasmodic movement, in a dorsi-ventral or 

 anisotropic organ ; (c) that method which depends on the 

 sudden expulsion of water at the moment of death from a 

 hollow organ, previously filled with liquid ; and (d) the 

 method in which the death-point is determined from the 

 sudden reversal of a thermo-mechanical response-curve. I 

 shall, in the course of the present chapter, describe the first 

 three of these, leaving the fourth method to be treated in the 

 next chapter. 



(a) Determination of the death-point by electrical response. — 

 As regards the electrical method, I have shown elsewhere ' 

 that the response of normal galvanometric negativity is cha- 

 racteristic of the living condition of a plant-tissue. When the 

 plant is killed, by any means whatsoever, this normal response 

 disappears. At the moment of death from rise of temperature, 

 therefore, we shall have the abolition of the normal negative 

 excitatory response. But at or beyond this point, on the other 

 hand, we may have the positive response of hydrostatic dis- 

 turbance replacing the true excitatory effect. By this electrical 

 mode of investigation, I have been able to determine the 

 death-points of different plants. In the following table, for 



' Bose, I\esponse in the Living and Non-Liz'iiii^; p. 62. 



