206 COMPARATIVE ELECTRO-PHYSIOLOGY 



is very definite and practically the same for all phanero- 

 gamous plants. Among the mechanical methods, that 

 which depends on the thermo-mechanical curve, giving 

 the death-point by a sudden inversion, is specially accurate. 

 Of an equally precise character is the death-point obtained 

 by the inversion of an electrical curve, and also that which 

 is given by reversal of the electrical response. And it is in 

 the highest degree remarkable that the points of inversion 

 in the mechanical and electrical curves respectively, together 

 with the point of reversal of the electrical response itself, 

 should so exactly coincide. 



