EVOLUTION OF THE BKAItf. 283 



these two may vary, T + K = the total func- 

 tion. Probably in most cases the time and dura- 

 tion of both functions are alike ; hence we may 

 use either T or K to indicate time and duration of 

 the total function of the subject. The element or 

 attribute " time " is thus made an essential part of 

 the description. 



In an investigation as to the development or 

 evolution of a child's brain, we may proceed as 

 follows, investigating only its development in 

 growth, the changes in its material structure; at 

 different ages its size, weight, anatomy, histology, 

 chemistry, etc. 



Again, we may investigate its kinetic functions 

 by recording nerve-muscular signs. We find, at 

 first, purely spontaneous movements, automatic, and 

 not readily inhibited or controlled by light and 

 sound. At three months old these movements are 

 co-ordinated upon stimulus by light, later by sounds 

 also. At this still early age, the special combina- 

 tions and series of movements following upon a 

 stimulus are uncertain, not uniform upon similar 

 stimulations. Thus food placed in front of a new- 

 born infant produces no uniform series of move- 

 ments of its hands ; food placed in front of a boy 

 of six years stimulates him by the sight of it to 

 move his hands and eat the bread and butter, his 

 movements being so uniform movements of hands, 

 head, mouth, jaw, etc. that we may call them 

 uniform or automatic because they occur so regu- 

 larly, so uniformly. Has this automatic action 

 resulted from external agencies ? 



