ANIMAL ELECTRICITY" 



565 



of a cat's foot is made to sweat by stimulation of the sciatic nerve, th 

 pouring out of the sweat is accompanied by an increase (a positive 

 variation) of the ingoing current. If, however, the effect of the nerve 

 be abolished by atropine, such a result is no longer obtained. The 

 normal current of the skin is found to be increased by direct excita- 

 tion, this increase or positive variation being reduced or abolished 

 by the local application of atropine, chloroform, or carbon dioxide. 



SEC. -01 -02 



FIG. H04. ANALYZED DIPHASIC RESPONSE OF SARTOEITJS AT 18 C. (Keith Lucas.) 



Salivary Glands. In the submaxillary gland, which has been 

 especially studied, the resting current flows through the gland from 

 the surface to the hilus, and therefore from the hilus through the 

 galvanometer to the surface (Fig. 306). When the gland is made to 

 secrete by stimulation of the chorda tympani nerve, the hilus becomes 

 still more galvanometrically positive an effect abolished by atropine. 

 Stimulation of the cervical sympathetic nerve has the opposite effect. 



Retinal Currents. If the eyeball and the retina be connected to 

 a galvanometer, a " current of rest " is observed, the direction of 

 which depends on whether the outer or inner surface of the retina 



