298 ORIGINAL ARTICLES. 



the recent state. The weights of these three portions of the hardened 

 encephalon, respectively, were 75 oz. avoirdupois, 1*3 oz. and *2 oz. ; 

 so that the recent cerebrum would have weighed 11 GQ oz., the cere- 

 bellum 202 oz.,and the pons and medulla "31 oz. 



According to these calculations, the cerebrum in the young Chim- 

 panzee is to the cerebellum, as 5*75 to 1 nearly. In the adult man it 

 was found by Dr. John Eeid to be about 8 5 to 1 ; and in the new 

 born child it appears from Huschke and others, to be at least 13 to 1. 

 In a child five years of age the ratio would probably be somewhere 

 between these. By the test of weight then, which I am not aware 

 to have been applied before, to the separate parts of the Simian brain, 

 the cerebrum of the Chimpanzee is found to be much smaller, in pro- 

 portion to its cerebellum, than is the case in man. 



To carry still further this mode of comparison, we may next con- 

 trast the relative weights of the cerebrum and body, and then of the 

 cerebellum and body, in man and the Chimpanzee, by which double 

 contrast, we see, at once, the relative superiority in size of the cere- 

 brum, in man, and of the cerebellum, in the ape. Assuming the ratio 

 of 1 to 40, between the brain and the body in an adult healthy man, 

 and of 8"5 to 1, between his cerebrum and cerebellum, then the pro- 

 portion between his cerebrum and his body will be 1 to 447 and 

 between his cerebellum and his body 1 to 380 ; whilst in our Chim- 

 panzee, the proportions as estimated above would be 1 to 22*6, and 

 1 to 131. It is desirable that many more observations on the weights 

 of these separate parts of the encephalon in the several races of men, 

 and in animals, as compared with their bodies, should be collected : 

 they would yield neater results than those arising from measurements, 

 for reasons which will presently be abundantly illustrated. 



General form, dimensions, and relative position of the parts of the 

 Mieephalon. Notwithstanding the care with which the Chimpanzee's 

 brain had been placed, with its upper surface resting on a bed of 

 cotton wool, in the spirit in which it had been preserved, a marked 

 distortion of its shape had taken place, by the time it was perfectly 

 hardened. Such a deformation must occur, to a greater or less extent, 

 in every brain removed from its cranial case, and placed in a similar 

 position. Its effects are surprising to those who are not familiar with 

 them, and cannot be correctly estimated, without comparing the so 

 altered brain with a cast of the interior of the cranial cavity, from which 

 this soft, pulpy, organ has been extracted. It influences the form of 

 the encephalic mass in all three of its cubical dimensions. The general 

 results are, a slight lateral bulging of the cerebral hemispheres, oppo- 

 site the parts tied together by the corpus callosum ; a more marked 

 falling asunder of the hemispheres at each extremity, but especially 

 behind ; a moderate elongation of the hemispheres ; and lastly, a very 

 marked, compensating flattening, on both the upper and under surfaces, 

 but especially, on the former, so that its characteristic convexity is 

 completely lost. Moreover, the cerebellum, together with the pons 

 and medulla, drag on the cerebral peduncles, so as to make these latter 



