TOO FUNCTIONS OF THE BRAIN. 



accommodation for near vision is always accompanied by 

 contraction of the irides. 



Regulation of the Movements of Expression. On this 

 subject, information is derived from the observation of 

 disease. When the muscles of one side of the face 

 are rendered temporarily or permanently inactive by com- 

 pression or destruction of the portio dura in the Fallopian 

 canal, the affected side loses its expression, and is drawn 

 to the opposite side. The affected cheek is flabby, and 

 the eyelids cannot be closed (lagophthalmus paralyticus\ 

 in consequence of which, tears flow over the cheek, while 

 the exposed eyeball is rotated upwards. If the lesion is 

 on the central side of the genu, these phenomena are 

 accompanied by asymmetry of the posterior arch of the 

 fauces, consequent on inactivity of the levator palati, as 

 well as by loss or impairment of hearing ; moreover, the 

 salivary glands of the affected side cannot be excited to 

 reflex secretion. 



The Functions of the Brain comprising those of the Cor- 

 tical Convolutions, Corpora Striata, and Optic ThalamL A 

 frog which has been deprived of its hemispheres, acts in all 

 respects as a normal frog, excepting that it is incapable either 

 of interpreting its sensations, or of initiating voluntary acts. 

 The condition of the brainless mammalian animal is 

 analogous. It is subject to emotion, and acts in such a 

 way as to show that it is influenced both by impressions 

 received through the nerves of common sensation and 

 through those of sight and hearing, but it is incapable of 

 understanding, remembering, or willing. All of its acts 

 are of the kind described on p. 78. Any direct inter- 

 ference with the brain as, e.g., by compression of its sub- 

 stance, or by arrest, or great diminution of its circulation 

 (as in syncope), annuls consciousness. Although at first 

 sight the development of the hemispheres seems in animals 

 to exhibit only a very general relation to that of the 

 mental faculties, it can be shown that the relation between 



