THE DEVELOPMENT OF THE BRAIN 151 



to the appropriate ganglionic masses an organ in which 

 impressions are sorted, associated, and stored, so that 

 in the process such a complicated state as consciousness 

 is evoked, and judgment and memory are made possible. 

 Upon the completed cortex, complex pictures are woven 

 and subsequently interwoven with others, and stored in 

 that endless array of memories which constitutes ex- 

 perience, and forms the basis of judgments. But these 

 things came slowly in evolution. The reflections from 

 different centres and different channels found their way 

 to the cortex gradually, and in definite order. First to 

 obtain cerebral re-representation was the sense of smell, 

 and this, of course, for the reason that smell impressions 

 play such a predominant part in the life of a lowly animal. 

 Placed right at the extreme fore-end of the primitive 

 animal body, the great olfactory sense organs and the 

 olfactory parts of the brain may be regarded as giving 

 the animal its first impression of anything with which it 

 came in contact. As the animal moved through life it 

 tested and learned of life by this the most forward sense 

 channel, and it was this which first demanded something 

 more in brain development it demanded a place in which 

 to store up the impressions it was repeatedly gathering. 

 The most primitive cerebral cortex is an olfactory cortex, 

 and, following the nomenclature of Elliot Smith, we will 

 term it the Archepallium (see Figs. 59 and 60). This, then, 

 was the birthright of the Protomammal, a definite cerebral 

 pallium, a small and limited storehouse, but a storehouse 

 full of possibilities; for it was one in which impressions 

 of one kind were already laid by ready for use at any 

 time, to which others might conceivably find their way, 

 and in which all might possibly be blended and retained 

 in that intellectual medley comprised in memory and 

 experience. Even in existing Reptiles some slight 

 advance upon a pure olfactory cortex is seen, for " tactile 

 paths have made their way into the hitherto almost 

 exclusively olfactory cerebral hemispheres, and estab- 



