204 Messrs. W. M. Bayliss and J. R. Bradford. [Feb. 11, 



Electrical Condition during Rest. 



Dog. — The cutaneous surface of the gland is in the great majority 

 of cases negative to the hilus, both when examined as above de- 

 scribed and also when the gland is removed from the animal and 

 led off. 



In four experiments amongst twenty-four, the outer surface of the 

 gland was positive. In two cases the outer surface was at first 

 positive, but subsequently became negative, and in one case it was at 

 first negative but subsequently became positive. 



The electromotive force of the current of rest varies very much 

 both in different cases and in the same case at different times ; 

 thus in the former case it may vary from y 1 ^- volt to volt, but 

 owing to a variety of structures (muscles, &c.) being unavoidably 

 injured in the preparation, not much stress can be laid on this point. 



Gat. — Out of twenty experiments on the submaxillary gland, in 

 fifteen the surface of the gland was positive to the hilus, in three the 

 surface of the gland was negative, in one the surface was at first 

 negative and subsequently became positive, and in one the surface 

 was at first positive and subsequently became negative to the hilus. 



Hence, although a corresponding amount of injury is inflicted on the 

 tissues in the case of the cat as in the dog, yet on the whole the 

 resting current is opposite in its sign in the two cases. 



Excitatory Changes. 



Dog. Chorda Tympani. — On throwing an induction current into 

 the chorda tympani, a very well-marked deflection of the galvano- 

 meter is always observed of a sign indicating that the outer surface 

 of the gland becomes negative to the hilusi Although in different 

 dogs the amount of this deflection varies, yet never have we failed to 

 obtain it. 



Frequently this variation is not the sole one observed, its course 

 being interrupted by a second deflection showing the outer surface of 

 the gland to become positive. This second variation, however, is by 

 no means always observed, and more especially it is not seen if the 

 first or main phase is very large, being then indicated only by a 

 slight temporary arrest in the deflection caused by the first phase. 

 The latent period of the variation is short, being about 0'37", as 

 measured by the capillary electrometer. The deflection quickly 

 reaches a maximum and begins to diminish before the cessation of the 

 excitation, returning quickly towards zero, but as a rule leaving a 

 slight after-effect. 



Atropine, in doses of 5 — 10 mgrma., abolishes the main phase of the 

 chorda variation in from 2 — 3 minutes from its injection into the 

 pleura. In those cases in which this phase only had been observed, 



