

THE CEREBRAL CORTEX. 

 BY E. A. SCHAFER. 



CONTENTS. GENERAL FUNCTIONS, p. 697 Results of Removal of whole Cortex, 

 p. 698 of one Hemisphere, p. 704 Results of Artificial Excitation, p. 705 

 Character of Muscular Contractions resulting from Excitation, p. 707 Other 

 Phenomena resulting from Excitation, p. 713 Effects on Respiration, p. 713 

 On Circulation, p. 714 On the Pupil, p. 715 On the Secretions and on the 

 Muscular Tissue of the Viscera, p. 716 Heat Centres, p. 717 Epilepsy, p. 

 718 SPECIAL LOCALISATIONS The Motor Areas and Centres, p. 722 

 Sensory (?) Functions of Motor Areas, p. 724 Results of Stimulation and 

 Removal of Particular Areas, p. 732 Associated Movements, p. 735 The 

 Principal Parts of the Motor Cortex of the Monkey, p. 736 The Head and 

 Eyes Area, 738 Face Area, p. 740 Arm Area, p. 743 Leg Area, 744 Trunk 

 Area, p. 745 The Motor Centres in the Orang, p. 745 The Motor Centres in 

 Man, p. 747 The Sensory Areas of the Cortex, p. 749 The Visual Area, p. 752 

 -The Auditory Area, p. 761 The Olfactory and Gustatory Areas, p. 763 The 

 Localisation of Tactile Sensibility, p. 766 Latent Regions of the Cortex, 

 p. 769 Hypothesis of Association Centres of Flechsig, p. 771 Aphasia, p. 774 

 Connections of Cortical Centres with one another and with Lower Centres, 

 p. 776. 



G-ENERAL FUNCTIONS. 1 



THE cerebral cortex is the seat of the intellectual functions, of 

 intelligent sensation or consciousness, of ideation, of volition, and of 

 memory. That this is so is proved by the observation in man of cases 

 of defective cerebral development and destructive disease. An 

 individual with defective cerebral development is idiotic, in proportion 

 to the amount of defect. It has not hitherto been shown that idiocy is 

 associated especially with defect of any one particular region or of one 

 hemisphere more than the other ; probably in all cases of marked idiocy 

 the defect is bilateral. Similarly, an individual with extensive destruc- 

 tion of the cortex cerebri, the result of accident or disease, becomes 

 mentally defective, the memory is lost, sensations are no longer rightly 

 appreciated, ideas are confused, and the volitional power is disordered, 

 diminished, or absent. These changes occur, not only as the result of 

 affections of the cortex, but also from lesion of the fibres which connect 

 the cortex with the " lower levels " of the central nervous system. 



The term " level " in connection with the central nervous system was 

 introduced by Hughlings Jackson to imply stages of complexity of the sensori- 



1 An admirable historical and critical account of the functions of the brain, including 

 many references to the views and researches of both older and more modern investigators, 

 is given by Professor J. Soury in the article "Cerveau," in Richet's "Diet, de physiol.," 

 Paris, 1897, fascs. 5 and 6. For a fuller discussion of many of the questions raised in the 

 recent rapid progress of research in this branch of physiology, than can well be introduced 

 here, the student may be referred to that article ; and the more so because the views 

 which are taken by Professor Soury are, on some questions, different from those which 

 are advocated here. See also "Le systeme nerveux," by the same author, Paris, 1899, 

 which is an extension of the above article. 



