Different results are obtained by a comparison of equally large individuals of both sexes. According to Marchand the weight of the female brain is, without exception, lighter than that of men of the same size. But this method is as incorrect as a comparison with the size of the body. It takes for granted what remains to be proven: a direct relation between the size of the body and the weight of the brain. Blakeman, Alice Lee and Karl Pearson have determined on the basis of English data and measurements, that there is no noticeable relative difference in the weight of the brain between man and woman; that is, a man of the same age, stature and skull measurements as the average woman, would not differ from her in regard to the weight of his brain.[152]
Even Marchand points out that the smaller size of woman’s brain may be due to the greater fineness of her nerves. Grosser says: “Indeed, this has not yet been determined by means of the microscope, and would be difficult to determine. But we must point to the analogy that the eye-ball and the cavity of the ear are also somewhat smaller with woman than with man, yet these organs are no less fine and serviceable. Another, perhaps the chief reason, for the lighter weight of the woman’s brain may be found in her weaker muscular development.”[153]
Inasmuch as the differences are rooted in the nature of sex, they can, of course, not be altered. But to what extent these differences in blood and brain can be changed by a different mode of life (nourishment, physical and mental culture, occupation, etc.) cannot be definitely determined for the time being. That modern woman differs from man to a greater extent than primitive woman or the woman of inferior races, seems to be established, and when we consider the social development of woman’s position among civilized nations during the past 1000 or 1500 years, it seems only too obvious.
The following shows the capacity of the female skull according to Havelock Ellis (assuming the capacity of the male skull to be 1000):
| Negro | 984 |
| Hottentot | 951 |
| Hindu | 944 |
| Eskimo | 931 |
| Dutch | 913 |
| Russian | 884 |
| German | 838 to 897[154] |
| Chinese | 870 |
| English | 860 to 862 |
| Parisian, 19 yrs. | 858 |
[154] According to five different authors: 838, 864, 878, 883, 897. For Prussia (Kupfer), 918; for Bavaria (Rause), 893.
The conflicting statements among the Germans show that the measurements have been taken among greatly differing material, both in regard to quality and quantity, and that therefore they are not absolutely reliable. But the figures clearly show one thing: that Negroes, Hottentots and Hindu women have a considerably larger capacity of the skull than the German, English and Parisian women; and yet the latter are far more intelligent.
A comparison of the brain-weights of well-known deceased men shows similar contradictions and peculiarities. According to Professor Reclam, the brain of the scientist Cuvier weighed 1830 grammes; that of Byron, 1807; that of the famous mathematician Gauss, 1492; of the philologist Hermann, 1358; of the Parisian prefect Hausmann, 1226. It is said that the weight of Dante’s brain also was below the average weight of the male brains. Havelock Ellis gives us similar information. He reports that the brain of an unknown person, weighed by Bischoff, had a weight of 2222 grammes, while the brain of the poet Turgeniew weighed only 2012 grammes; the third largest brain was that of an imbecile; the brain of a plain workingman that was also examined by Bischoff, weighed 1325 grammes. The heaviest female brains weighed between 1742 and 1580 grammes; two of these were taken from women who had suffered from mental derangement. On the congress of German anthropologists, which was held in Dortmund in August, 1902, Professor Waldeyer stated that an examination of the skull of the philosopher Leibnitz, who died in 1716, had shown that its contents only measured 1450 cubic centimeters, which corresponds to a brain weight of 1300 grammes. According to Hausemann, who examined the brains of Mommsen, Bunsen and Adolph v. Menzel, Mommsen’s brain weighed 1429.4 grammes; it accordingly did not exceed the average brainweight of an adult man. Menzel’s brain weighed only 1298 grammes and Bunsen’s less still—1295 grammes, below the average male brainweight and not much above the brainweight of a woman. Those are striking facts that completely overthrow the old assumption that intellectual abilities could be measured by the capacity of the skull. After an examination of the English data, Raymond Pearl comes to the following conclusion: “There are no proofs of a close relation between intellectual abilities and brainweight.”[155] The English anthropologist, W. Duckworth, says: “There is no proof that a heavy brainweight is accompanied by great intellectual ability. Neither the brainweight, nor the capacity of the skull, nor the circumference of the head, where they could be determined, have been of any use as a measure of intellectual abilities.”[156] Kohlbruegge, who has during recent years published the results of the examinations of human brains of many races, says: “Intelligence and brainweight are entirely independent of one another. Even the greater brainweight of famous men is not sufficient proof, since it exceeds the general medium weight, but not that of the upper classes to which these men belonged. But by these statements I do not seek to deny that brainweight can be increased, especially by excessive study during youth, which may account for the heavier brainweights and the greater skull capacity of the upper classes and of scholarly persons, especially when—as is usually the case among the well-to-do—excessive nourishment is added. This increase in weight by mental over-exertion has its dark sides also, as is well known. Lunatics often have very heavy brains. The main point is that it cannot be proven that intelligence (something entirely different from productiveness) has any relation to weight. It is true of the external formation also, that until now, no connection could be shown between certain forms and higher mental development, intelligence, or genius.”[157]
It is established, then, that we cannot draw conclusions from the brainweight as to mental qualities, as little as we can draw conclusions from the size of the body as to physical strength. The large mammals, such as elephant, whale, etc., have larger and heavier brains; yet in regard to proportional brainweight they are excelled by most birds and small mammals. We have some very small animals (ant, bee) that are far more intelligent than much larger ones (for instance, sheep, cow), just as people of large stature often are mentally inferior to persons of small and insignificant appearance. According to all probability the mass of the brain is not the determining factor, but its organization and the practice and use of its powers.
“In my opinion,” says Professor L. Stieda, “the difference in psychic functions can doubtlessly be accounted for by the finer construction of the gray matter, the nerve cells, the white matter, the arrangement of the blood-vessels, the construction, form, size and number of nerve-cells, and last but not least, their nutrition, their metabolic assimilation.”[158]