THE FUNCTIONAL DEVELOPMENT OF THE 

 CEREBEAL COKTEX IN DIFFERENT 

 GROUPS OF ANIMALS. 



IN connection with my investigations on the psychic 

 development of young animals,* it seemed important, 

 in regard to the question of physical correlation, to 

 ascertain, in so far as that is possible by experimental 

 methods, at what period the cortex of the brain becomes 

 functionally active. Nothing, to my knowledge, has 

 been done of late years on this subject. I determined, 

 therefore, to give it as complete an investigation as 

 possible. Realising that breadth of investigation was 

 important, as well as thoroughness, the experiments 

 have not been confined to one or two groups of animals, 

 but cover several. This, together with the desire to 

 report only what was thoroughly well determined, has 

 extended these investigations over a long period and 

 involved much labour. 



Only those individual animals have been used the 

 exact age of which was known, and, as a matter of 

 fact, most of them were born and kept under my own 

 observation, so that their exact age and, in many cases, 

 their breeding, etc., were known. It is scarcely neces- 

 sary to state that the experiments were rendered 

 painless. 



* The author has thought it well to introduce here just so much of 

 this paper as will make the following one somewhat clearer. Both 

 appeared in the first instance in the Transactions of the Royal 

 Society of Canada, in 1896. 



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