CHAP. XXI.] 



OF THE HUMAN BRAIN. 



377 



certainly imply the existence, in the Brain of Man, of a 

 remarkable capacity for growth and development, under 

 the long-continued influence for generation after genera- 

 tion of those modes of life and cerebral activity which 

 are almost inseparable from existence in a more or less 

 Civilized Community. 



In studying the external configuration of the Human 

 Brain, it will be most expedient, in the first place, to look 



VIJI. 



FIG. 133. Brain of the ETottentot Venus, side view. (Vogt, after Gratiolet.) 

 F, Frontal lobe ; P, parietal lobe ; 0, occipital lobe ; T, temporal lobe ; C, Cere- 

 bellum ; Po, pons Varolii ; V M, medulla oblongata ; S, Syivian fissure ; R, fissure of 

 Rolando ; P S, parallel fissure, a 1 , Upper fold of frontal convolutions ; a 2 , middle 

 fold of frontal convolutions ; a 3 , lower fold of frontal convolutions. A, Ascending 

 frontal (or anterior central) convolution ; B, ascending parietal (or posterior central) 

 convolution ; I 1 , &?, 63, upper, middle and lower folds of parietal convolutions ; 

 e 1 ., c 2 , c 3 , upper, middle and lower folds of temporal convolutions ; d 1 , d s , ds, upper, 

 middle and lower folds of occipital convolutions. 



to the characters of the organ as it exists in one of the 

 lower races of Mankind. We may then advantageously 

 compare one of these simpler types with the more highly 



