The human species - A. de Quatrefages

On no occasion, perhaps, has this question been treated more thoroughly and by more competent judges than by the Paris Anthropological Society in the great discussion of 1861. Many speakers took part in it, but the two principal champions of the rival doctrines were Gratiolet on the one hand, and M. Broca upon the other. Some of their statements, if taken literally, would lead us to imagine that an impassable gulf lay between them. If, however, we read them again, after the excitement of the moment has passed away, we find, from the summaries which they themselves have drawn up, that such is by no means the case, and that, far from their being divided in principle, it would not be difficult to effect an understanding between them.

Gratiolet considers “that power which lies in the brain, and which can only be estimated by its manifestations,” far more important than weight or form. But he is far from absolutely refusing to recognise the influence of cerebral development; he allows that below a certain limit the human brain no longer performs its functions in a normal manner. This limit he places at 900 grms. (31·74 oz.) in the female.

M. Broca raises the number to 907 grms. (31·99 oz.), and adds that, in the male, the limit is 1049 grms. (37 oz.). He attributes great importance to the volume of the brain, estimated either directly, by weight, or by the capacity of the cranium. But on several occasions he protests most strongly against the intention which might be imputed to him, of wishing to establish an absolute relation between the development of the intelligence and the volume or weight of the brain. “No well-instructed man,” he says, “would ever think of estimating the intelligence by measuring the encephalon.”

The two following tables, borrowed from M. Broca, will suffice to show the truth of these words:

AVERAGE WEIGHT OF THE BRAIN IN MAN.

	grms.	oz.
From 1 to 10 years	985·15	(34·75).
From 11 to 20 years	1465·27	(51·68).
From 21 to 30 years	1341·53	(47·67).
From 31 to 40 years	1410·36	(49·74).
From 41 to 50 years	1391·41	(49·07).
From 51 to 60 years	1341·19	(47·30).
From 61 and upwards	1326·21	(46·77).

WEIGHT OF THE BRAIN IN SOME EMINENT MEN.

NAME.		AGE.	PROFESSION.	WEIGHT OF BRAIN.
NAME.		AGE.	PROFESSION.	grms.	oz.
1.	Cuvier	63 years	naturalist	1829·96	(64·54).
2.	Byron	36 years	poet	1807·00	(63·73).
27.	Lejeune·Dirichlet	64 years	mathematician	1520·00	(53·61).
34.	Fuchs	52 years	pathologist	1499·00	(52·87).
43.	Gauss	78 years	mathematician	1492·00	(52·62).
52.	Dupuytren	58 years	surgeon	1436·00	(50·65).
92.	Hermann	51 years	philologist	1358·00	(47·90).
158.	Haussmann	77 years	mineralogist	1226·00	(43·24).

The numbers placed before the name of each person indicate the position held by the latter in the list of 347 cases of healthy brains taken by M. Broca from the general table of Wagner. We find that the celebrated mineralogist Haussmann stands almost half-way down the list, and that he is separated from his eminent colleagues by a considerable number of unknown examples. Again, we observe that the weight of his brain is 100 grms. (3·5 oz.) below the average weight of men of his age. On the other hand, in all the other cases the weight of the brain was above the average.

The exception presented by Haussmann, the manner in which all these eminent men are scattered among their ordinary brethren, should be sufficient to make us reject all exaggerated connection of the magnitude of the intelligence and that of the brain. This result is still more striking if we group these same numbers as Gratiolet has done, calculating the mean of the contiguous weights. We thus obtain for the first group (Cuvier, Byron) an average weight of 1818·48 grms. (64·14 oz.); for the second (Dirichlet, Fuchs, Gauss, Dupuytren) 1487 grms. (52·44 oz.); for the third (Hermann, Haussmann) 1292 grms. (45·57 oz.). The latter is below the average weight of German brains, that is to say, of the fellow-countrymen of the two eminent men in question.