514 SCIENCE PROGRESS. 



In the same year, the same observers investigated the 

 "secretion currents" of the lingual glands of the frog. 

 Here, again, an ingoing "current of rest" was observed, 

 and upon excitation of either glosso-pharyngeal or hypo- 

 glossal nerves, but especially of the former, a triphasic 

 variation appeared, the phases being in the order, ingoing, 

 outgoing, with final ingoing. This effect was obviously 

 due to the interpolation of an outgoing phase during the 

 course of a long- lasting ingoing current. 



Luchsinger also, two years later, experimented with the 

 glands of the snout of the pig, goat, cat and dog, and while 

 he found the "rest current" ingoing, could only elicit an 

 ingoing "current of action" on excitation of the cervical 

 sympathetic or the infra-orbital nerves. Difference of re- 

 action of the electrodes made no difference to the direction 

 of the " rest current," and the glandular nature of the " action 

 current " was again indicated by its abolition by atropine. 



The cases, then, that have so far been considered, show 

 that it is the rule for the "current of rest" of a eland to 

 be ingoing in direction, while the "current of action" 

 appears to be in the same direction in the majority of 

 cases, though there are cases and conditions in which the 

 galvanometer shows an opposite (outgoing) current, or a 

 di- or even tri-phasic variation, composed of two opposed 

 currents of unequal strength and duration. 



It is to the merit of Bayliss and Bradford to have been 

 the first to point out clearly the fact that it is probably 

 always the rule for the electrical changes in secretion to be 

 diphasic, and, moreover, that the separate phases may be 

 associated with differences of physiological action in the 

 gland cells, related possibly even to specific sets of nerve 

 fibres. 



These observers made extended investigations into the 



palm of hand, and skin over deltoid muscle, such diverse stimuli as tick- 

 ling the face, smelling acetic acid,^a sound, or even the expectation thereof, 

 mental arithmetic, etc., may cause a marked current indicative of relatively 

 richly glandular palm skin, negative to poorly glandular shoulder skin. 

 Withdrawal from other disturbances than those needed for the experiment 

 is necessary for success with this experiment. 



