RESPONSE OF DIGESTIVE ORGANS 



335 



are subsequently absorbed by the tissue, as in corresponding 

 cases, by the stomach of animals. From the study of the 

 responsive peculiarities of so primitive a type of stomach, we 

 might then expect to gain much light on the action of more 

 complex and highly specialised digestive organs. In order 

 first to obtain the true current of rest, 

 I took a young pitcher which had 

 previously been kept free from all 

 disturbance. I next made electrical 

 connections, by means of non-polaris- 

 able electrodes, with the inner (glan- 

 dular) and outer surfaces of this 

 pitcher respectively. As some excita- 

 tory reaction may be induced in a 

 highly excitable organ, even by the 

 contact of normal saline, the cotton 

 threads in connection with these non- 

 polarisable electrodes were moistened 

 with the natural secretion of the 

 pitcher itself. On carrying out the 

 experiment under these ideal condi- 

 tions, I found, as I had expected, 

 that the current of rest flowed from 

 the outer non-glandular to the inner glandular surface, the 

 latter thus being galvanometrically positive. 



In investigating next the excitatory reaction, 1 obtained 

 three different types of responses negative, diphasic, and 

 positive characteristic of certain definite conditions. Before 

 entering upon the details of these experiments, it is advisable 

 to discuss here the probable significance of the negative and 

 positive electrical reactions observed. 



We have seen that a slice of tissue from the 1 pulvinus of 

 Mimosa excretes water under excitation. The electrical 

 reaction under these circumstances is one of galvanometric 

 negativity. But during the process of recovery, when the 

 tissue is absorbing water, this negativity diminishes, a change 

 that is tantamount to that increase of positivity with which 



FIG. 200. Pitcher of Ne- 

 penthe^ with lid removed. 



