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The principal object of the paper was to point out the 

 first gradations from the perfect structure of the brain in 

 man, and for this purpose the author related the dissection 

 of the brain of the chimpanzee {simia troglodytes, Lin.) and of 

 two human idiots, from which he was led to conclude that the 

 primary deviations in the anatomy of the brain were to be 

 found in the essential structure of the locus niger, of the cor- 

 pus Jimbriatum, siad. of the corpora oiivm-ia, — in the existence 

 of the volute strice in the fourth ventricle, of the corpora can- 

 dicafiiia, and of calcareous granules in the pineal gland, — in 

 the degree of intermixture of the white Jilanietits of the arbor 

 vitce, the distinction of the anterior crura o? the fornix , and 

 lastly the decussations of the pyramids. By the dissections 

 it was evident that the brain of the chimpanzee possessed a 

 superior structure to that of the natural human idiot. 



As the author had previously ascertained that all the 

 plexuses in the brain are conjoined, and all the cerebral and 

 spinal nerves are incorporated with the parts from which 

 they are said to arise, he was led to infer that the functions 

 of the brain are not confined to particular parts of the surface, 

 but that all the parts exercise a mutual influence on each 

 other, that its powers and operation are systematic and har- 

 monious, instead of the effect of different parts of the brain 

 acting independently and often in opposition to each other. 

 He stated a number of facts contradicting the opinion of the 

 cerebellum being designed to produce the sexual instinct, as 

 taught by Gall and his followers. He ascribed the origin of all 

 instincts to the organs to the operations of which the instincts 

 are subservient. He argued that if instinctive impulses were 

 to originate in the brain, they would interfere with all its 

 higher functions. The author further considered the per- 

 fect continuity and incorporation of the nerves with central 

 parts of the system, as sufficient to account for the functions 

 of sensation and voluntary motion, without the interposition 

 of nervous fluid. 



