CONTENTS. 



the encephalon Microcephalies Weight of micro- 

 cephalic brains according to sex Argument for the cor- 

 relation of weight with intelligence Brain-weight and 

 cranial capacity of eminent men Cranial capacity of 

 murderers Macrocephalic brains Physiological supe- 

 riority of mean forms Brain-weight in the insane 

 Proportional development Relation of brain-weight to 

 mental disease Pathological changes affecting brain- 

 weight in the insane Resume. 



CHAPTER VII. 

 THE NERVE ELEMENTS 141 



Histological basis First form of central system 

 Description of cell Human types Chemical characters 

 Various shapes rOutgrowths Construction of cell 

 Changes during development Volume of neuroblast 

 Changes in the size of the elements with age Nerve 

 fibres The medullary sheath Size of young cell-bodies 

 and fibres Calculation of the average size of nerve 

 elements and their number in man. 



CHAPTER VIII. 

 DEVELOPMENT OE XEKVE ELEMENTS 163 



Time of development The elements at birth Schiller's 

 observations The frog Observations by Birge Origin 

 of sensory fibres The frog compared with the mammal 

 Significance of medullary substance Regeneration- 

 Means by which the brain-weight changes with age 

 Influence of stature on brain- weight Significance of 

 brain- weight in different races In the two sexes 

 Among animals Anatomical relations alone explained. 



CHAPTER IX. 



ARCHITECTURE OE THE CENTRAL NERVOUS SYSTEM 176 

 AT MATURITY 



Architecture at maturity Shape of skull Shape of 

 brain Effect of deformation On weight Relative 

 development of lobes Causes of change in shape- 

 Bilateral symmetry Weight of right and left hemi- 

 spheres Decussation Segmentation Areas of spinal 

 cord Cephalic development Brain and cord in 

 animals. 



