ELECTROMOTIVE PHENOMENA IN GLANDS. 521 



while the "action current" of a part rich in "goblet cells,'* 

 and clear of " club cells," such as the lip, conforms in its 

 conditional modifications to that described by Biedermann 

 for ordinary mucous surfaces, the current from the body 

 skin, which is richly set with " club cells," but sparsely so 

 with "goblets," does not agree with Biedermann's story, 

 but gives an ingoing " action current " to a stimulus that 

 elicits an outgoing current in the mucous lip. The dis- 

 charge of M alapteninis is peculiar in that the nervous sides 

 of the electrical discs become positive to the non-nervous, 

 and the observation as regards the direction of the action 

 current of the club cells of the eel just mentioned, gives 

 physiological backing to Fritsch's idea, and would serve to 

 explain the anomalous direction of the " shock". 



We have now briefly reviewed the main points of the 

 electrical phenomena of glands, and it yet remains to attempt 

 some criticism of the various theories advanced. 



One point appears clear at the start, namely, that any 

 theory of the "action current," if it is to be in any way 

 satisfactory, must also be applicable for explanation of the 

 " current of rest ". A piece of exsected frog's skin or nicti- 

 tating membrane exhibits marked variations of potential, 

 often quite equal to anything that can be called forth upon 

 excitation, and these spontaneous cell changes must be of 

 the same kind as those excited by nerve stimulation. Again, 

 artificially induced reduction of the "current of rest," or 

 such as is noted in animals " out of condition," at once pro- 

 foundly affects the result of excitation. 



In the face of such facts, the demarcation surface theory 

 proposed by Hermann to explain the "current of rest" 

 cannot stand, at any rate in- the form in which he put it 

 forth ; for if the ingoing " current of rest " is merely due to 

 the chemical alteration that the surface cells of a glandular 

 membrane have undergone during growth, how shall we 

 explain the complete "reversal" and " recovery ' : that can 

 be repeated experimentally any number of times in succes- 

 sion ? That epithelial surfaces, which are not secretory in 

 nature, can give ingoing currents of rest, has been demon- 

 strated in the case of the non-glandular skin and crop of 



