340 



COMPARATIVE ELECTRO-PHYSIOLOGY 



downwards. This indicates an increasing positivity of the 

 glandular surface. 



The results which have thus been described, in the case 

 of the fresh pitcher, and of one subjected for a long period to 

 the stimulus of food, are fully compatible, it will be observed, 

 with the theory of digestion as a diphasic process, in which 

 galvanometric negativity is associated with a predominant 

 secretion, and the subsequent galvanometric positivity with a 

 predominant absorption by 

 the glandular membrane. 



FlG.. 204. Photographic Record 

 of Responses of Pitcher in 

 Intermediate Stage, having 

 Attracted a Few Insects 



Note here the occurrence of two 

 phases in constituent responses, 

 positive being predominant. 



FIG. 205. Photographic Record of Re- 

 sponses of Pitcher in Third Stage, the 

 whole Glandular Surface thickly 

 Coated with Insects. Stimuli applied 

 at Intervals of two Minutes 



The response here is in the positive phase, 

 direction of current being from non- 

 glandular to glandular. Note also the 

 multiple character of responses to 

 single stimuli. 



It is also important to notice that while in the fresh 

 condition the glandular surface is positive, and in the 

 moderately stimulated condition negative, yet positivity of 

 the glandular surface is not always to be taken as a sign of 

 its fresh condition. For we have here seen that under long- 

 r.ontinued stimulation, the electrical condition is apt to be 

 reversed to one of positivity, 



