34-8 THE GROWTH OF THE BRAIN. 



In this history of organisation there are many errors, 

 happily for the most part transient. Here belong 

 all those vague suggestions of a second personality 

 which in growing children are so perplexing and so 

 numerous. Sometimes these phases periodically recur, 1 

 and at adolescence they are most accentuated. They 

 represent the disharmony of the first steps in change 

 and progress, and, like mirror-script, gibberish talk and 

 the various forms of general inanity are but intermediate 

 phases between the imbecility of the infant and the 

 intelligence of the adult. 2 The intensity with which any 

 form of exercise is carried on during the growing period 

 leaves its trace, and the absence of it at the proper time 

 is for the most part irremediable. We should hardly 

 expect much appreciation of colour in a person brought 

 up in the dark, however good his natural endowments 

 in this direction. Thus any lack of early experience 

 may leave a spot permanently undeveloped in the central 

 system a condition of much significance, for each 

 locality in the cerebrum is not only a place at which 

 reactions, using the word in a narrow sense, may occur, 

 but by way of it pass fibres having more distant con- 

 nections, and its lack of development probably reduces 

 the associative value of these also. 



It is now recognised that thought can be carried 

 on in terms of the several senses. In this connection 

 Fraser 3 has made an examination of certain philosophic 

 writers which indicates that particular writers or schools 

 prefer sense-images of one mode in their speculative 

 thought, and he suggests that much of the failure to 

 be mutually comprehensible, depends on the fact that 



1 Siegert, Die Periodicitdt in der Entivickelung dcs Kindes- 

 natur, 1891. 



2 (Houston, Neuroses of Development, 1892 ; Warner, Physical 

 Expression (International Scientific Series), 1893. 



3 Fraser, A m. Journ. of Psychol,, 1892, 



