HEMISPHERES. 



429 



portion of the cerebral surface, however, remains concealed in such 

 a manner that it cannot possibly be subjected to examination, viz., 

 the entire base of the brain, with the under surface of the ante- 

 rior and middle lobes (i, 2); the upper surface of the cerebellum 

 (3) and the inferior surface of the posterior lobe of the cerebrum 

 which covers it (4) ; that portion of the cerebellum situated above the 

 medulla oblongata(o); and the two opposite convoluted surfaces in 

 the fissure of Sylvius (e, 7), where the anterior and middle lobes of 

 the cerebrum lie in contact with each other. The whole extent, 

 also, of the cerebral surfaces which are opposed to each other in the 

 great longitudinal fissure (Fig. 141), throughout its entire length, 

 are equally protected by their position, and 

 concealed from external examination. The 

 whole of the convoluted surface of the brain 

 must, however, be regarded as of equal im- 

 portance in the distribution of the mental 

 qualities; and yet it is evident that not 

 more than one-third or one-quarter of this 

 surface is so placed that it can be examined 

 by external manipulation. It must further- 

 more be recollected that the gray matter of 

 the cerebrum and cerebellum is everywhere 

 convoluted, and that the convolutions pene- 

 trate to various depths in the substance of 

 the brain. Even if we were able to feel, therefore, the external 

 surface of the brain itself, it would not be the entire convolutions, 

 but only their superficial edges, that we should really be able to 

 examine. And yet the amount of gray matter contained in a given 

 space depends quite as much upon the depth to which the convolu- 

 tions penetrate, as upon the prominence of their edges. 



While phrenology, therefore, is partially founded upon acknow- 

 ledged physiological facts, there are yet essential deficiencies in its 

 scientific basis, as well as insurmountable difficulties in the way of 

 its practical application. 



CEREBELLUM. The cerebellum is the second ganglion of the 

 encephalon, in respect to size. If it be examined, moreover, in 

 regard to the form and disposition of its convolutions, it will be 

 seen that these are much more complicated and more numerous 

 than in the cerebrum, and penetra3 much deeper into its substance. 

 Though the cerebellum therefore is smaller, as a whole, than the 



Transverse section of B K A i x, 

 showing depth of great longi- 

 tudinal fissure, at a. 



