CHAPTER IV. 



THE WEIGHT OF THE BRAIN AND SPINAL CORD. 



Historical Objects of examination Interpretation Constituent 

 elements Sources of error Corrections Reasons for not 

 fusing results Percentage of body-weight Determination of 

 brain weight in the living Nomenclature Spinal cord 

 Encephalon Subdivisions Grey and white matter Chemi- 

 cal reaction Percentage of water Specific gravity Weight 

 of adult brain Proportional development Weight of the 

 basal ganglia Weight of spinal cord Conclusions. 



THE weight of the encephalon, or that portion of the 

 nervous system contained within the cranium, has often 

 been recorded, especially during the last century. The 

 earlier observations were desultory and few in number, 

 while the later ones are both more systematic, more 

 accurate, and more numerous. Nevertheless very pre- 

 cise results are demanded, and until still greater care is 

 taken it will not be possible by increasing merely the 

 number of observations to pass much beyond the stand- 

 point of to-day. In his Elements of General Anthro- 

 pology Topinard T has given a list of the observations on 

 the weight of the brain up to the year 1885. The 

 entries in the table there printed show a total of 6,035 

 observations on the sane, and 4,147 on the insane. 

 Since 1885 there have been recorded some 3,500 more, 

 mainly on the insane, so that there now exists a grand 



1 Topinard, Elements CL Anthropologie gdnJrale, 1885. 

 8 4 



