CONTENTS. V 



PAGE 



PHYSIOLOGY OF THE CRANIAL NERVES 186 



Physiology of the Third Cranial Nerve 137 



Fourth Cranial Nerve 138 



" " Fifth or Trigeminal Nerve 139 



' " Sixth Nerve 143 



" " Facial Nerve 144 



" " Glosso-Pharyngeal Nerve 145 



" " Pneumogastric Nerve 146 



Spinal Accessory Nerve 149 



" Hypoglossal Nerve . 150 



PHYSIOLOGY OF THE SPINAL NERVES 150 



PHYSIOLOGY OF THE SYMPATHETIC NERVE 151 



Functions of the Sympathetic Nervous System 153 



CHAPTER XIX. 



THE SENSES , 158 



Common Sensations 158 



Special Sensations 159 



THE SENSE OF TOUCH . 162 



THE SENSE OF TASTE 168 



The Tongue and its Papillae .169 



THE SENSE OF SMELL 175 



THE SENSE OF HEARING 179 



Anatomy of -the Organ of Hearing 179 



Physiology of Hearing 186 



Functions of the External Ear 186 



Functions of the Middle Ear; the Tympanum, Ossicula, and Fenestrce . 187 



Functions of the Labyrinth ......... 191 



Sensibility of the Auditory Nerve 193 



THE SENSE OF SIGHT 196 



The Eyelids and Lachrymal Apparatus 196 



The Structure of the Eyeball .197 



Optical Apparatus 203 



Accommodation of the Eye 206 



Defects in the Apparatus , . . .211 



Spherical Aberration . . , 212 



Chromatic Aberration 213 



The Blind Spot 215 



Visual Purple 218 



Color Sensations . . . 223 



