CoGiTic Evolution of ]Man 621 



action. For all are aware how perfectly the nostrils, the eyes, 

 and the limbs are linked up in their correlated connections with 

 each other and w^ith the brain. But, since the neuro-muscular 

 innervation of the limbs seems in considerable part to be associ- 

 ated with nerves that spring from the ventrally derived brain 

 lobes that became the medulla and later also the cerebellum, 

 more and more complex correlation between the cerebrum, the 

 optic lobes, the medulla, and the cerebellum would ensue. 



Hence the highly intelligent actions that are characteristic 

 of many carnivores like the dog, the fox, the cat, and the racoon; 

 of some rodents like the mouse, the rat, and the beaver; of 

 many monkeys like those already referred to (p. 565). But as 

 traced in Chapter XX, when the forelimbs became increasingly 

 used as prehensile, tactile, selective, fighting, and building or- 

 gans, through increasingly upright posture amongst the higher 

 monkeys, in corresponding ratio would increase take place in 

 the main brain centers. Thus, in all of the above-named ani- 

 mals, multitudes of greatly varied sense impressions would be 

 passed in daily to the brain, and while not a few might at once 

 be summated and responded to by proenvironal effort, very 

 many would become, if we may so express it, stored stimulant 

 impressions that increased the neuratin substance of the brain, 

 but to which no recognizable response would be made. Such 

 however would tend, we consider, to start the rudiments of 

 conceptSy owing to the abmidance, the variety, the complexity, 

 and the correlation of the percepts poured in on the brain 

 during the active hours of each day. 



So the dawnings of concepts or evolving reason seem clearly 

 to be traceable in all of the above groups, specially in the higher 

 Carnivora, Rodentia, Proboscidea, and Primates. But in 

 connection with the valuable comparative studies of Edinger, 

 Herrick, and Johnston on the forebrain of vertebrates, which 

 functioned prmiitively as an olfactory sense center, but which 

 later in fishes and higher vertebrates gave origin to the cerebral 

 lobes, it might well be objected that the upbuilding of this most 

 important pair of lobes could more appropriately have been 

 originated or effected from the midbrain or optic lobes. 



