SIZE AXD WEIGHT. 



581 



Com2)arativc measurement of the extent of surface of the Com'olution~s of the 

 Cerehrum- and its lobes. 



Surface of each lobs separately. 



Free and deep 



! surfaces of Cerebrum. 



WEIGHT OF THE SEVEKAL PARTS OF THE ENCEPHALON. 



As the result of observations made in reference to this subject, on the brains 

 of .53 males and 34 females, between the ages of twenty-five and iifty-five, Dr, 

 J. Reid has given the following table : — 



Average weight of cerebrum 



., cerebellum 



., pons and medulla oblongata 



., entire encephalon . . 



Males. 



07.. drs. 



13 15| 



.". 4 



1.0? 



.-0 



Females, 

 oz. drs. 



.38 12 

 4 12^ 

 1 Ok 



DifEerence. 



oz. drs. 

 o 3| 

 7| 

 0^ 



.-) 11 



With these results the observations of Huschke, derived from a special ex- 

 amination of the brains of 22 females and 38 males, mainly agree. 



From this it appears] that the proportionate weight of the cerebellum to 

 that of the cerebrmn is, in the male, as one to Sf. and in the female, as 1 to Sj. 

 The cerebellmn attains its maximmn weight from the twenty-fifth to the 

 fortieth year ; but the increase in weight after the foiu-teenth year is shown to 

 be relatively greater in the female than in the male. The whole cerebellum apart 

 from the pons and medulla is heavier in the male ; the lateral lobes of the 

 cerebellum are also heavier iu the male. In the male the vermiform i^rocess 

 increases gradually from the twentieth to the fiftieth year ; in the female it 

 remains stationary during that period, and after the fiftieth year diininislies 

 rajiidly. 



In the new-born infant the ratio of the weight of the cerebellum to that of 

 the whole brain is strikiagly different from that observed in the adult, being, 

 according to Chaussier, between 1 to 13 and 1 to 2G ; by Cruveilhier it was found 

 to be 1 to 20. Huschke found the weight of the cerebellum, medulla oblongata, 

 and pons together in the new-bom iufant, as compared with that of the brain, 

 to be in the proportion of 1 to 15, and 1 to 13. In the adult the proportions were 

 1 to 7, and 1 to G. 



In most mammalia, the cerebellum is found to be hea\'ier in proportion to the 

 cerebrum, than it is in the human subject ; in other words, the cerebrum in man 

 is larger in i^roportion to the cerebellum. 



Scemmerring pointed out the fact that the brain is larger, in iiroportion to tho 

 nerves connected with it, m man than in the lower animals. 



A comparison of the width of the cerebrmn with that of the medulla oblongata 

 shows that the proportionate diameter of the brain to that of the medulla ob- 

 longata is greater in man than in any animal, except tlie dolphin, in which 

 creature, however, it must be remembered that the cerebral lobes exhibit a dis- 

 proportionate lateral development. The width of the cerebrum in man, as 



