356 ^ AVERAGE WEIGHT OF THE BRAIN IN THE 



relation to the bulk of their bodies than that of man. According to Cuvier, the brain 

 of the seal is larger in proportion to the body than in man, and the same is the case 

 in some of the American monkeys, as well as in some small birds. The fact of this 

 smaller proportionate size of the brain in man has been well ascertained, although it 

 is not of much moment; and that of the absolute lesser magnitude of his brain is now 

 notorious. For instance, the brain of a sperm whale of fair average size is about 900 

 cubic inches in magnitude ; so that it is seen that the weight of the brain in each 

 species of animal is strictly proper to it, although it may and must nevertheless bear 

 some relation to the size of the animal. And such is also the case in the different 

 races of man. Each race has its own proper size of brain, influenced, it may possibly 

 be, by the stature of the race, but certainly not necessarily controlled by it. 



In looking into the older writers of only forty or fifty years ago, it is at once seen 

 how little was accurately known respecting the weight of the brain and other allied 

 subjects. The great anatomist Von Scemmerring, at an earlier period, considered that 

 the brain did not increase in size after the third year. The Wenzels deferred the 

 period of full development to the seventh year, which was considered to be confirmed 

 by Sir Wm. Hamilton's researches. Gall and Spurzheim put off this period to about 

 the fourteenth year. Now it is known that the brain goes on increasing in volume 

 till adult age, and until the full maturity of the organization is attained. It has also 

 been demonstrated that the weight of the brain decreases materially in old age, which 

 was formerly regarded as very doubtful.* The fourth series in our table, embracing 

 eleven males of from sixty to ninety years of age, proves a remarkable diminution of 

 weight, possibly of specific gravity also. 



It is not requisite in this place to enter into the consideration of the immense ad- 

 vances made in the anatomy and physiology of the brain, upon other points; a sub- 

 ject which would demand a volume that could alone be produced by an accomplished 

 anatomist. Enough has been said to prove that the general views respecting the 

 growth and magnitude of the brain have been rendered much more worthy of confi- 

 dence by modern researches, to justify the importance of the inquiry to which this 

 memoir is devoted, and to confirm the view here maintained, that brain-weight must 

 not be regarded otherwise than as a special endowment proper to each distinct race 

 of man. The present communication is not of such value as it might have been had 

 the data fallen into abler hands; still, it is hoped that it may be of some use in aiding 

 the advancement of knowledge respecting the encephalon now in progress. 



The inquiry itself is of much moment in its bearings upon an hypothesis which is 



*Tiedemann expresses these doubts, although he does not participate in them. His words are to this effect: 

 Whether the weight of the brain diminishes in old age is a point upon which anatomists are divided in opinion. 

 The brothers Wenzel did not observe any remarkable diminution. Hamilton, lilvewise, holds it in doubt. 

 Desmoulins, on the contrary, found that in old people, after the fiftieth year, the brain not only exhibits a 

 smaller absolute weight, but it is also specifically lighter. 



