STRUCTURAL CULMINATION 971 



animal its kern scent and to niaiiy species a jjioteetivc accessory in proxiding 

 warning of the appioaeli ot enemies. According Id all signs the sense of smell 

 is on {hv wane in the primates. The archaic rhinencephalon becomes less 

 |jrominenl, the olfactory hull) and tract grow smaller and lose tluir intimate 

 incorporation in the orl)ital surface of the brain. Other sense capacities, such 

 as vision, hearing and the sense of touch, the latter especially as developed 

 in the hand and hngers, ha\e replaced the sense ol smell by substituting for 

 it receptors both ol the distant and contact \ariety. Dependence upon these 

 latter sensor\' organs perha[3s places the animal in more adxantageous rela- 

 tion to Its eiuironment, in certain respects at least. 



The primordial dexclopment ol the olfactory sense is ])reeminentl\ con- 

 nected with the process ol obtaining food. It is concenable that the constant 

 influx ol Impulses by this a\enue of sensation might be deterrent, if not 

 ])reiudicial to tlu' further de\elopment of other faculties. In the race of life, 

 the procuring of food must aKva\s take its place among other obiects of much 

 importance to the needs of tlu' organism. It ma\ , of course, l)e claimed in this 

 connection that tlu' u])shot of all action is in the interest of maintaining lifi'. 

 The olfactory sense, therefore, can no more be said to retard the de\elopment 

 of such purposes than any other sense. But w ith the possible exct'ption of that 

 small degree of protectixe insurance and sexual direction which the olfactory 

 sense proNides, its mam and decisixe mllueiux' is eoniu'cted with the location 

 and ideiitilication ol lood sup|)l\-. Llence the dellorescence in this department 

 of sensory organization m the [jrimate max be considered as of adxantage 

 in developing other and mori' w idel\ productiw courses of reaction. 



Again the decrease m the oliactorx portion ot the brain is in direct 

 proportion to e\j)ansions in the frontal lobe. It thus appears that, howcxer 

 much the animal max' sulfer bx decreased elliei(>ney in this spluat' of sensi- 

 bilitx, it gams immeasurablx in tlu- combinations of experience made j:)ossible 

 through increments to the frontal area. 



