EVOLUTION AND THE AFTER-LIFE. 



55 



ligcuce increases niid a larger range of actions is performed, tliis power 

 to predict how any individual will act is gradually lost. 



Advancing step by step upward in the mammalian series, certain 

 changes in the development of the cerebrum occur, accompanied in 

 each instance by the introduction of new faculties or the improvement 

 of old ones. Throughout tlie lower orders fishes, reptiles, and birds 

 the cerebrum, though constantly increasing in relative size from mere 

 nodules of gray matter less in size than the optic ganglia, up to 

 masses of much greater bulk than the sensorium, still retains the same 

 general appearance two smooth oval bodies, one on each side of the 

 median line, and gradually appi'oaching each other as they enlarge 

 until they meet, then extending forward and backv/ard so as more and 

 more to cover in and hide the sensorium. These represent the hemi- 

 spheres ; and this is the condition of brain which is found in the lower 

 mammalians. Associated with this cerebral development we find u 

 psychical condition not very far advanced beyond that already con- 

 sidered as pertaining to birds; namely, action partly prompted by 

 instinct, and partly controlled by intelligence, as especially seen in 

 the rodentla, or gnawing animals. The perfection of instinct and want 



Fig. 5. Bf.ain of Rabbit (I!oderii): 1. Olfactory Ganglia; 3. Cerebral nemisplieves; 3. Cere- 

 bellum ; 4. Spiual Cord. Other parls of Sensorium covered by Cerebrum. 



of reasoning power in regard to certain actions are well illustrated in 

 an example quoted by Dr. Carpenter. It is that of a beaver which a 

 gentleman kept in his house, and who, notwithstanding his unfavor- 

 able surroundings, w^ould exercise his instinct for dam-building on all 

 occasions ; for materials he appropriated brooms, warming-pan, walk- 

 ing-sticks, baskets, boots, and books, or in fact any thing portable 

 within his reach, arranging them in the most approved style of beaver 

 architecture, although he had never witnessed the process in others. 

 He exercised the same skill, also, in preparing himself a dwelling. 

 The absurdity of the whole process from a reasoning point of view 



