LECTURE IV. 



97 



Physiological experiments have proved that it is the primitive 

 brain only which possesses sensibility ; that all cex'ebral nerves 

 spring onlyj'rom the grey ganglia it contains, and that this 

 part is mainly connected with sensation and motion. 



On farther examining the base of the brain we perceive im- 

 mediately above the primitioe hrain on both sides of the medulla 

 a mass divided into lobes and lamince. This is the cerebellum, so 

 little developed in man and most apes, that, on being viewed 

 from above, it seems entirely covered by the brain proper. 



If a vertical section be made through the cerebellum, the 

 medullary substance is seen covered with grey matter, produc- 

 ing a tree-like figure, which the old anatomists designated the 



Fig. 30. The Brain of the so-called Hottentot-Venus : top view, after 



Gratiolet. 



L. Longitudinal fissure, 

 fissiu-e. F. Frontal lobe. P. 

 lobe. Po. Pons Varolii. C. 



R. Eolando's fissure. V. Posterior transverse 

 Parietal lobe. O. Posterior lobe. T. Temporal 

 Cerebellum. V. M. Medulla oblonsrata. 



