00 ANDREW JACKSON HOWE. 



possesses small cerebral hemispheres, and a thin cover- 

 ing of gray neurine, almost without convolutions, and 

 the bird in picking up corn spread as a decoy, has not, 

 after stooping to pass under a gate, sense enough to 

 escape from the trap by the way of entrance, which is 

 still left open. 



Geese are endowed with a low order of cerebral 

 matter and cephalic ganglia, yet the stupid creatures, 

 in a wild state, have intelligence enough to fly north 

 upon the approach of the breeding season, in order 

 that they may have a safe and healthy place to .rear 

 .their young. They have learned by experience that 

 there is no security for them in rivers, bayous, and 

 lagoons infested with alligators, huge gars, and other 

 voracious enemies. 



In the comparison of degrees of intelligence, and 

 the quantity and quality of neural matter, it is inter- 

 esting to observe that all animals in geological periods 

 prior to the Tertiary were endowed with a scanty 

 amount of brain ; but at the commencement of the 

 Eocene, when mammals made their first appearance, 

 there occurred rapid and marked progress in the de- 

 velopment of the cerebral hemispheres. It would 

 seem as if a striking improvement in brain-making 

 was introduced somewhat abruptly, and that the pro- 

 gressive tendency was kept up until the cerebral evolu- 

 tion culminated in the elaboration of man's elevated 

 brain. 



A purposive action originates in brain or neural 

 knots that generate intelligence. In some of the lower 

 vertebrates the spinal cord acts as a generator and dis- 

 tributing center of nerve force. However, the move- 

 ments produced by irritating the spinal nerves of de- 

 capitated Saurians, are not directed by intelligence ; 



