546 



COMPARATIVE ELECTRO-PHYSIOLOGY 



critical point is reached. And here, though the temperature 

 still goes on ascending at the same rate as before, we see a 

 sudden reversal in the characteristic curve of resistivity, 

 showing that the hitherto increasing has suddenly become a 

 decreasing resistance. This abrupt inversion represents the 



FIG. 328. FIG. 329. FIG. 330. 



FIG. 328. Photographic Record of the Morographic Curve taken by 



Method of Resistivity Variation in Pistil of Hibiscus. Critical point 



of inversion at 60*8 C. 

 FIG. 329. Photographic Record of the Morographic Curve taken by 



Method of Electro-motive Variation in Petiole of Musa. Critical point 



of inversion at 59-6 C. 

 FIG. 330. Photographic Record of the Morographic Curve taken by 



Method of Mechanical Response in Filament of Passiflora. Critical 



point of inversion at 59 '6 C. 



excitatory effect which occurs at the point of initiation ot 

 death, and is in the present case at 6o'8 C. (fig. 328). 



It is astonishing to find that the morographic curves 

 obtained from different specimens, by three methods so 

 different as the mechanical, the electro-motive, and that of 



