OTHER ASPECTS OF THE FUNCTIONS OF THE BRAIN. 723 



But after such an incision the animal suffers a paralysis of the movements 

 connected with the area, like that resulting from the removal of the gray 

 matter of the area ; and the operation is said to be followed by degenera- 

 tive changes in the area, and degeneration of the pyramidal fibres starting 

 from it. Some of this effect may be due to nutritive changes brought about 

 by injury to the pia mater and division of bloodvessels ; but it cannot be 

 wholly accounted for in this way ; it appears as if the life of the area is 

 curtailed when its nervous ties are broken. 



We may conclude then that we are not justified in speaking of con- 

 sciousness of volition, or other psychical processes, even admitting that these 

 fail when the cortex is removed, as being functions of the cortex in the same 

 way that we speak of the functions of other organs ; they are rather func- 

 tions of the connections of the cortex with the other parts of the central 

 nervous system. 



We should add that they are also functions of the connections of the 

 several parts of the cortex with each other. All our knowledge goes to 

 show that psychical processes are dependent on, or are in some way asso- 

 ciated with the cortex ; but whatever classification of psychical functions 

 we adopt, we are wholly unable to make out any localization of functions, 

 such as we can make out for movements, visual sensations and the like. 

 Even taking the broad and elementary division into " the emotions" and 

 "the intellect," we cannot satisfactorily allot either division to any particu- 

 lar part of the hemisphere. In dogs, removal of particular parts of the 

 hemispheres has indeed been observed to change the character of the ani- 

 mal, converting for instance a vicious, morose dog into a mild and inoffen- 

 sive one ; and removal of the front part of the hemisphere seems to have 

 frequently a marked effect in rendering the animal more impressionable and 

 excitable ; he becomes much more demonstrative and " gushing " in his 

 behavior than before. But these are mere hints, and the clinical histories 

 of disease in man do not enable us to say much more. Such knowledge as 

 we do possess rather tends to show that the psychical processes in proportion 

 as they become more complex involve a greater number of nervous factors, 

 and, therefore, have for their material basis a greater width of nervous area, 

 or in other words their localization becomes less definite. Thus, while we 

 may localize the beginning of a psychical process, a visual sensation for 

 instance, and one of its terminal acts, such as the issue of impulses along 

 the pyramidal tract, we cannot put our finger on the seat of the interme- 

 diate transactions. These even in the simplest process must be complex, 

 and must involve many factors. Our simplest conceptions of the external 

 world are based on a combination of visual sensations and tactile sensations. 

 It being granted that the visual sensation, in one phase of its development, 

 is connected with certain changes in some spot of the occipital cortex, there 

 must be some tie between this and the corresponding nervous seat of the 

 tactile sensation wherever that may be, and further ties between these and 

 other parts of the cortex. Hence, as we said, the psychical process is a 

 function of connections. 



Many of these ties are most probably furnished by the association fibres 

 passing from one part of the cortex to a neighboring part. We must also 

 probably admit that impulses, or, to use a more general word, processes, may 

 travel laterally along the tangle of the cortical gray matter, for this, like 

 the gray matter of the spinal cord, seems to form a physiological continuity, 

 no more broken by the fissures than is the cord by its segmental arrange- 

 ment ; and we know nothing as to the limits which must be placed on the 

 distance to which such processes may travel from their focus of origin. 

 Further, seeing how completely in the dark we are as to the reason why we 



