664 
The geveral conclusions deducible from the 
preceding statements are, that the human brain 
reaches and maintains its highest degree of de- 
velopement between the ages of 20 and 60; 
that the female brain is materially smaller than 
that of the male; that the proportion of the 
weight of the brain to that of the body de- 
creases with age, and the most marked 
diminution in this respect takes place between 
the ages of 20 and 30 years, although it has 
already begun at 5 years, and occurs veryide- 
cidedly at from 13 to 15 years; and lastly, that 
the great preponderance of the human brain 
over that of most of the lower animals depends 
upon the great developement of the cerebrum 
and cerebellum. 
It was formerly admitted, pretty generally, 
that the human brain was larger, both abso- 
lutely and relatively to the size of the body, 
than that of any other animal. This assertion, 
however, must now be received with some mo- 
dification. Exceptions to its superiority in ab- 
solute weight are found in the elephant and 
the whale. The brain of an African elephant, 
seventeen years old, which was dissected by 
Perrault, weighed 9 lbs.* The brain of an 
Asiatic elephant weighed, according to Allen 
Moulins, 10lbs.t Sir Astley Cooper dissected 
an elephant’s brain, which weighed 8 lbs. 1 oz. 
2 grs. (avoirdupois.){ Rudolphi found that 
the brain of a whale, 75 feet long, ( Balena 
mysticetus,) weighed 5 lbs. 104 0z., and that 
that of a narwhal ( Monodon monoceros, ) 17 to 
18 feet long, had a weight of 2lbs.30z, And 
there are likewise exceptions to the statement 
that the human brain is larger than that of other 
animals, relatively to the size of his body. 
Pozzi§ has shewn (as quoted by Tiedemann) 
that many small birds (for instance, the spar- 
row) have, in comparison to the size of their 
body, a larger brain than man; and Dauben- 
ton, Haller, Blumenbach, and Cuvier, found 
the brain of some of the smaller apes of the 
Rodentia, and singing birds, relatively to the 
size of the body, larger than in man.|| 
“ We must seek for the cause of man’s su- 
periority,” says Tiedemann, “ not merely in the 
greater bulk of his brain in comparison to that 
of his body, but regard must also be had to the 
size of his brain with respect to the bulk and 
thickness of his cerebral nerves, and likewise 
to the degree of perfection in its structure. 
Soemmering was the first to show that the 
human brain, in comparison to the size and 
thickness of the nerves, is larger than that of 
any other animal, even the elephant and whale, 
both of which have an absolutely larger brain 
than man. Blumenbach’s, Obels’, Cuvier's, 
Treviranus’, and my own researches have suffi- 
* Descr. Anatom. d’un Elephant, Mém. de 
l’Acad. des Sciences de Paris, t, iii. 
+ An anatomical account of an Klephant. Lond. 
1682. 
Quoted in Tiedemann’s paper on the Brain of 
a Negro. Phil. Trans. 1836. 
§ Observat. Anatom. de Cerebro, an sit in homine 
proportione majus, quam in aliis animalibus ? 
|| Tiedemann’s paper on the Brain of the Negro, 
before quoted. See also Leuret’s Table, Anat. Comp. 
du Systeme Nerveux, t. i. p. 420. 
NERVOUS SYSTEM. (Nervous Centres. Tart ExcePuaton.) 
ciently corroborated this. It is also satisfac 
torily shewn that the organization of the huma 
brain is far superior to that of any other anima 
not even excepting those apes which bear th 
closest resemblance to man.’ Pe 
The following conclusions, which Tiedema 
deduces from his observations, are so imp 
tant that I cannot refrain from inserting th 
here.* “a 
“ 1. The weight of the brain of an adult m 
European varies between 3 Ibs. 2 oz. and 4 
60z. The brain of men.who have distinguish 
themselves by their great talents is often 
large. The brain of the celebrated Cuy 
weighed 3 Ibs. 11 oz. 4 dr. 40 grs. avoirdup 
or 4 lbs. 11 oz. 4 dr. 30 grs. troy wei 
The brain of the celebrated surgeon Du puytr 
weighed 4 lbs. 10 oz. troy weight. (Both 
these eminent individuals, it ought to be- 
marked, died with the brain in a state of 
ease.) The brain of men, with feeble in 
lectual powers, is, on the contrary, often ¥ 
small, particularly in congenital idiotismus. 
brain of an idiot, fifty years old, weighed ~ 
1 Ib. 8 oz. 4dr., and that of another, forty ye 
of age, weighed but 11b. 110z. 4 dr. . 
“2. The female brain is lighter than tha 
the male. It varies between 2 Ibs. 8 oz. 
3 lbs. 11 0z. troy. I never found a fer 
brain that weighed 4 Ibs. The brain of a. 
an idiot, sixteen years old, weighed only 
60z. 1dr. The female brain weighs, on 
average, from four to eight ounces less 
that of the male ; and this difference is aln 
perceptible in a new-born child. 
“ 3. The brain arrives, on an average, @ 
full size towards the seventh or eighth | 
Soemmering says, erroneously, that the 
does not increase afier the third year. 
and Spurzheim, on the other hand, are o 
nion that the brain continues to grow till 
fourteenth year. The brothers Wenzel 
shewn that the brain arrives at its full gi 
about the seventh year. This is confirme 
Hamilton’s researches.” 
(The reader will perceive that these : 
ments do not exactly accord with the resi 
Dr.John Reid’s observations. It seems pro 
that the data upon which Tiedemann’ 
sions were founded have been too limi 
number. In calculating the weight of the 
in adolescence and adult age, some alle 
should be made for the greater propo 
water at the former period; the qua 
that fluid being at those ages 72 and 7 
in 100 respectively, according to L’Héri 
“4. Desmoulins 1s of opinion thatth 
decreases in old people. From this” 
stance he explains the diminution ~ 
functions of the nervous system and 1 
tual powers. The truth of this assert 
not as yet been determined. The br 
Wenzel, and Hamilton deny it. J 
. It is mpeene ey brain of 
eighty-two years old, was v ma 
selighed buts Ibs. 2 oz. 3 dr., aa the bi 
a woman, about eighty years old, wei 
* Loc. cit. p, 502. 
