322 THE OUTGO OF ENERGY 



the sciatic nerve of this side. Place non-polar- 

 izable electrodes on the bare muscle of the 

 thigh and on the skin of the leg. Connect the 

 electrodes to a rheochord arranged for compensa- 

 tion by the bridge method, as shown in Fig. 47. 

 Place the capillary electrometer in a short cir- 

 cuit. Bring the meniscus into the field, and 

 note its position. Open the short-circuiting key. 

 Move the slider along the wire until the meniscus 

 returns to its original position. Now stimulate 

 the sciatic nerve with the tetanizing current. 



A negative variation will be seen. If the skin 

 current was slight, the variation may be positive. 



The greater part of the skin current is doubt- 

 less a secretion current, but not all. Weak cur- 

 rents have been obtained from skin devoid of 

 glands, for example, the eel's skin. Hermann 

 attributes this current to the degeneration which 

 accompanies the change of the nucleated cells of 

 the corium to the dead scales of the outer 

 epidermis. 



A strong secretion current may be obtained 

 from the skin of the foot (cat). On stimulation 

 of the sciatic nerve, the current is increased 

 (positive variation). 



In the submaxillary gland, the hilus is positive 

 to any point on the external surface of the gland. 

 Stimulation of the chorda tympani nerve, secre- 



