ELECTROMOTIVE PHENOMENA IN GLANDS. 513 



contractile sheath) their electromotive force exceeds that of 

 the epidermis, with the effect of giving a positive variation 

 of the "epidermic" current of rest. In this way Hermann 

 explains the diphasic variation most frequently observed, 

 viz., a short outgoing current (negative Vorschlag), followed 

 by an ingoing current, and is of definite opinion that while 

 the electromotive force of the " action current " is glandular, 

 that of the " rest current " is of epidermic origin. 



Bayliss and Bradford, who subsequently looked into the 

 matter, consider that the " rest current " of the frog's skin 

 is partly epidermic and partly glandular, since corrosive 

 sublimate reduces the "rest current" without cutting out 

 the "action current," while subsequent treatment of the 

 skin with atropine, while it cuts out the " action current," 

 also still further reduces the "current of rest". Time of 

 year is also considered by these observers as an important 

 factor as regards the nature of the action current, outgoing 

 currents predominating during and just before the breeding 

 season, while during the rest of the year an ingoing phase 

 is the rule. 



Before passing to the most recent work upon the cur- 

 rents of the frog's skin glands, it will, perhaps, be convenient 

 to briefly mention the other cases in which gland currents 

 have been studied. 



Hermann and Luchsinger, in 1 878, discovered the presence 

 of an ingoing " secretion current " in the sweat glands of the 

 pad of the cat's foot, upon excitation of the peripheral sciatic, 

 and this effect was abolished by atropine, and unaffected by 

 curare. They make no mention of any outgoing phase, 

 and as regards the current observed, state that it is quite 

 distinct, even when no exudation of sweat is visible. The 

 effect in the classical " Willkur-versuch " of Du Bois- 

 Reymond is considered as a sweat gland secretion current 

 on the ground of these results. 1 



1 Tarchanoff has recently shown that parts of the surface of the skin 

 of man, rich in sweat glands, are electrically negative to parts poor in such 

 structures, and, further, that the ingoing "secretion current" can be de- 

 veloped under the most diverse conditions of disturbance of the central 

 nervous system. Thus with leads of moistened cotton-wool from, say, 



