VARIOUS AGENCIES ON DEATH-RESPONSE l8l 



the physiological condition of the tissue. The rigor of 

 spasmodic contraction at death is, therefore, not to be 

 regarded as due to any coagulative action. And, indeed, the 

 theory of a connection between rigor and coagulation is now 

 generally discredited.' 



By the methods described, then, it is possible to study the 

 effect of various agencies in the modification of death-response : 

 in the case of anisotropic organs, by observation of their 

 lateral responsive movements, and in that of radial organs, 

 by the translocation of the point of inversion. I was next 

 desirous of discovering some still simpler means of determin- 

 ing the effects of various conditions in a qualitative manner. 

 This might be accomplished if we had a number of organs 

 exactly similar to one another, which would give some 

 unmistakable sign of death-response, at the point of occur- 

 rence, either immediately, or at some definite interval after- 

 wards. A certain number of these organs might then be 

 taken as standard, and the others subjected to the action 

 of various modifying influences. Any differences between 

 the temperatures concomitant with post-mortem symptoms 

 would now indicate the modifications produced by these 

 agents. 



In a certain sense, such an experiment may be carried 

 out with a number of leaves on the same plant of Mimosa. 

 But in such a case the organs to be compared are not very 

 numerous, and different leaves of exactly the same age 

 cannot be secured. 



Death-response in flowers. — This led me to investigate 

 whether, amongst flowers, specimens could be obtained which 

 would exhibit a death-movement at the critical temperature. 



' ' The causes which determine the varying resistance of different plants to 

 heat are quite unknown. The fact that a temperature of from 20° C. to 40° C. 

 kills certain plants, shows that in their case death is not the result of coagulation 

 of the plant-albumin. Further, some plants grow at 75° C, i.e. above the 

 temperature at which egg-albumin coagulates. Coagulation need not always 

 occur, for we must remember that the acid and alkali albumins are not coagulated 

 by heat.' — Pfeffer, Physiology of Plants, English edition, 1903, vol. ii. p. 230. 



