1862.] Brain of Man and the Brains of certain Animals. 409 



arity, together with other characteristics of its encephalon and other 

 structures, which had induced him to speak of it as " the last, the most 

 degraded of all the anthropomorphous apes ;" and to class it witli the 

 baboons, whilst he ranked the chimpanzee with the macaques, and the 

 orang with the gibbons. 



The last point of general configuration and measurement in which 

 the simious was contrasted with the human brain was that of their 

 several altitudes ; and it was shown that whilst men differed but little 

 inter se as to the height of their brains, it was precisely in this very 

 dimension that they differed, perhaps more widely than in any other, 

 from all apes whatsoever. 



After expressing his sense of the obligations which anatomy owed 

 to M. Gratiolet's analysis of the cerebral convolutions, the speaker 

 proceeded to give in detail the points of resemblance and of contrast 

 which that analysis had enabled us to detect as subsisting between 

 human or simious brains. The chief points in which, under this head, 

 the human was seen to contrast to advantage with the ape's brain were 

 two. First : The absence in man of " the external perpendicular 

 fissure," or, in other words, the filling up in him of what is more or 

 less of a chasm in the ape, by a large quadrangular mass of convolu- 

 tions. Second : The much greater size and complexity of the frontal 

 lobes. But it was shown that these differences affected what have 

 been called " secondary " and " tertiary " convolutions, and indeed 

 the latter of these chiefly, whilst the '* primary" convolutions, the 

 great typical 'lines and ridges, were the same in both classes of brains. 

 The apparatus for the mechanical, (and possibly also physiological,) 

 unification of the hemispheres, which is known as the corpus caUosum, 

 was stated to have in man just double the sectional area which it had 

 in the apes ; whilst the very lowest weight which an adult and healthy 

 human encephalon was recorded to have fallen to, was yet double, and 

 more than double, of the very highest which had ever been attained 

 in the weighing of an ape's brain. 



The results of the anatomical investigation were summed up thus. 

 " This doubly and more than doubly greater weight, the doubly 

 greater corpus callosum, that subquadrate lobule, lettered a and ^ in 

 the diagram, those complexly convoluted frontal lobes, 1, 2, and 3, are, 

 I believe, the four great points in which the human brain asserts its 

 superiority over that of the ape." 



The metaphysical or anthropological bearings of the investigation 

 might be summed up thus. How similar soever the simious might 

 be shown to be to the human brain, the argument which Bossuet drew 

 thence for the essential difference between mind and matter, would 

 but be rendered the stronger. If organs are common to man and to 

 brutes, one is necessarily forced to the conclusion that intelligence is 

 not attached to organs ; and the cogency of this argument, M. St. 

 Hilaire remarks, increases as the number of organs, common to the 

 two subjects of comparison, becomes more numerous and their resem- 

 blance more striking. 



