MAESHALL ON THE BBAIN OF A YOUNG CHIMPANZEE. 297 



excluding the pituitary body and pineal gland, weighed, immediately 

 after its removal from the cranium, exactly 15 oz. Deducting the 

 weight of the membranes afterwards removed (about \ oz.) and allow- 

 ing for the blood which these would contain, as well as for the short 

 piece of the spinal cord attached to the medulla, I calculated that 

 the nervous mass of the encephalon, in the quite recent state, 

 weighed at least 14 oz. This is an absolute weight, greater than that 

 of the brain of the young orang, described by Dr. Eolleston in the 

 last number of this Journal (p. 207), which weighed only 12 oz. It 

 also surpasses the absolute weights (9f oz. and 13£ oz.) of the brains 

 of a half grown male and of a female Chimpanzee, as given on the 

 authority of Professor Owen.* The brain of this young animal is, so 

 far as I am aware, the heaviest Simian brain yet on record. It is, 

 however, light indeed, in comparison with the weight of the human 

 brain in a child at about a corresponding period of dentition, which 

 would average at least 38 oz.f 



The ratio between the weight of the entire brain (14 oz.) and the 

 body (264 oz.) in our Chimpanzee, both taken in the recent state, 

 and without any sign of emaciation in the animal, is very nearly as 

 1 to 19, so that the brain was relatively heavier than in Dr. Rolle- 

 ston's young orang, in which the ratio was as 1 to 22*3. Fitting such 

 a brain to the body of the nearly adult female Chimpanzee, stated 

 by Prof. Owen, J to weigh 976 oz., the proportion would be as 1 to 

 70. The actual proportions observed in the female Chimpanzee 

 mentioned above, whose body weighed 680 oz., were 1 to 51. 

 But much as this, unusually heavy, young Simian brain raises previous 

 estimated ratios, it still remains far below the human proportion, 

 taken at a corresponding age. In Huschke's case of the child of six 

 years, the ratio was 1 to 11 ; and the proportion in the human adult, 

 is usually given as 1 to 36, or as 1 to 40, in cases of persons killed 

 or dying suddenly, whilst the body is in a healthy state. % This, how- 

 ever, refers to European brains. In regard to other races our infor- 

 mation is defective. 



At the end of several months, the entire brain of our Chim- 

 panzee, hardened and shrunk from the action of the spirit on its 

 watery, saline, and fatty ingredients, weighed only 9 oz. and a few 

 grains. In dissecting its right half, care was taken to weigh the 

 fragments of the cerebral hemisphere, and to ascertain the weight of 

 the right half of the cerebellum, and that of the pons, with the me- 

 dulla. The weight of the left half of the brain, which still remained 

 undissected, was also recorded. With these elements, and assuming that 

 every part of the brain had equally lost weight from the action of 

 the spirit upon it, it was easy to estimate approximately the separate 

 weights of the cerebrum, cerebellum, and pons, with the medulla, in 



* Quain's Anatomy by Sharpey and Ellis. Vol. ii. 433, note, 1856. Trans. 

 Zool. Soc. Jan. 1846. 



t See a table drawn up many years ago by myself, for Dr. Sharpey. Loc. 

 cit. p. 431. % Quain's Anatomy, ut antea, p. 433. 



