ADVANCED EXPERIMENTAL PHYSIOLOGY 159 



the nicitating membrane, causes separation of pupils and projects the 

 eye with the axis of the eyeball straight forwards. 



It constricts the blood-vessels of the skin, glands, arid mucous 

 membrane of the head. 



FIG. 160. Arterial pressure. Effect of exciting the stellate ganglion (accelerate 

 nerves). The time marked in seconds. (L.H.) 



It dilates the vessels in the bucco-f acini region of the dog. 



It excites secretions of the glands of the head, both salivary and 

 sweat glands. 



It erects the hairs in the cat and monkey over certain regions of 

 the face and scalp. 



V/%*^^ 



3*- G D 



FIG. 161. Record of arterial pressure. Cardiac acceleration produced by excita- 

 tion of the third dorsal root during the time shown by the signal line. (Bradford. ) 

 The time is marked in seconds. 



(2) The depressor nerve is an afferent nerve which runs from the 

 heart to the spinal bulb, and causes general dilatation of the blood- 

 vessels especially in the splanchnic region. (See Fig. 145.) 



It thus lowers the arterial pressure. The depressor is bound up 

 with the vagus in the dog. 



(3) The vagus is the inhibitory nerve to the heart, the motor nerve 

 to the bronchial muscles. 



It conveys both inhibitory and augmentary impulses to the 

 alimentary canal. 



