ON THE FUNCTIONS OF THE CEREBRUM 303 



or leas direct relationship, each with several sensorial zones, some 

 with all. 



" After their bilateral removal intelligence is affected, and especi- 

 ally is association of ideas interrupted. These central territories are 

 thus probably of great importance for the exercise of intellectual 

 activity, for the formation of mental images composed of several 

 sensory qualities, for the accomplishment of arts, such as the naming 

 of objects, speaking, &c. These functions are especially interfered 

 with in affections of the posterior centres of association. Clinical 

 observation establishes this fact, and thus justifies the legitimacy 

 of our division of the cerebral cortex into sensory centres (centres of 

 projection) and centres of association." (Archiv de Neurologic, ii., 

 1900, pp. 337-338.) 



The views of Flechsig were severely criticised by Hitzig, who, 

 however, is disposed to admit their general truth in a less positive 

 form ; and by Vogt, who directly contradicted many of Flechsig's 

 conclusions, and especially the thesis of the constancy and regu- 

 larity of myelination of the different systems of fibres. He is 

 inclined to look upon the majority of either early or late 

 myelinated fibres as projection fibres, and he regards the method 

 of Flechsig, though not valueless, as inferior to the more recent 

 methods of Campbell and Brodmann and himself, namely, the 

 study of the cell and fibre architecture of the adult cerebrum. 

 Monakow, in his criticism, drew attention to the small proportion 

 which the projection fibres form of the total mass of cortical fibres 

 of any of the convolutions, and he thinks that it is not possible, 

 however roughly it be done, to define the regions which are poor 

 in these fibres and those which are abundantly supplied with them. 

 Sachs, whilst admitting that the sense centres are sharply defined 

 off at an early period from the rest of the cortex, considered it 

 impossible to prove later, when myelination has advanced, that 

 medullated projection fibres do not pass to the centres of associa- 

 tion. Bianchi also has for many years strongly combated the 

 generalisations of Flechsig. He is not satisfied that myelination 

 of the various bundles of cortical fibres follows a constant law or 

 occurs in a regular sequence. He denies that the phenomena of 

 anatomical evolution need necessarily presuppose the existence 

 of functional activity of corresponding grade. He remarks, for 

 example, that there may be complete myelination of the supposed 

 centre for reading in the brain of an imbecile who has never learned 



