AVERAGE WEIGHT OF THE BRAIN IN MAN.
WEIGHT OF THE BRAIN IN SOME EMINENT MEN.
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, calculatingthe 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.
This remark is important. In the question under discussion it will not do to compare separately the celebrities who figure in Wagner’s table; we must connect them with the rest of mankind, with diseased, as well as with other brains. To act otherwise would be to give rise to the idea that we had wished to evade a difficulty by neglecting to turn the attention to the fact that, immediately after the brain of Byron, and long before that of Gauss, stands the brain of a madman. Are, then, genius and madness in such close relationship? Are the volume, the weight, and the peculiar characters of Cuvier’s brain indeed due to a hypertrophy which came to a standstill just at the right moment, as Gratiolet thought?
III. However abridged and curtailed this statement of facts may be, it seems to me sufficient to justify us in drawing conclusions equally applicable to individuals and to races.
We shall certainly not be accused of an exaggerated immaterialism if we estimate the action of the brain as we estimate the action of a muscle. Now experience and observation daily testify that in the latter volume and form are not everything. Functional energy often more than compensates for what is wanting with respect to mass. Many other organic systems would furnish similar facts, well-known to all doctors and all physiologists. To assert that the case is different with the brain would be, even in the absence of all direct observation, a purely gratuitous hypothesis, and, in the presence of Wagner’s tables, a contradiction of evidence. With hissmall brain, Haussmann, the correspondent of theFrench Institute, has evidently surpassed, in the matter of intelligence, almost all his large-headed contemporaries.
But, on the other hand, beyond a certain stage of decrease, the muscular apparatus becomes incapable of effort. We can readily understand that it should be so with the brain also. It is, therefore, most natural to find that, when it has fallen below a certain volume and weight, it gradually passes from weakness to impotence. Even M. de Bonald could not consider it strange, that anintelligencewhen provided only withimperfect or almost useless organs,should only manifest itself in an incomplete manner.
Thus, irrespective of all dogmatic or philosophic ideas, we are led to the conclusion that there is a certain relation between the development of the intelligence and the volume and weight of the brain. But, at the same time, we must allow that the material element, that which is appreciable to our senses, is not the only one which we must take into account, for behind it lies hiddenan unknown quantity,an x, at present undetermined and only recognised by its effects.
IV. Thus from this fact alone it follows that we cannot act with too much caution in forming an estimate of a race from the dimensions of its cranium, and the relative development of the bones of which it is composed. Gratiolet proposed to distinguishfrontal,parietal, andoccipital races, characterised by the predominance of the anterior, medial and posterior regions of the cranium and the brain. If we accept the word character as it is understood by naturalists, we shall have no objection to make to these denominations. But to go beyond that, to attribute to one or other of these races any kind of superiority by virtue of any one or other of these characters, would be mere hypothesis. In fact, the Basques, with their occipital dolichocephaly, are in no way inferior to the frontal dolichocephali of Paris.
V. In those phenomena, amongst which,à priori, we should be tempted to look for ethnological characters, we must give the first place toorganic evolutionat different periods of life. Now, the examination of facts establishesthe important fact, that, in this respect, all human races present a remarkable uniformity. When some slight differences are manifested, they show such coincidence with the action of the conditions of life, that it is impossible not to recognise the relation of cause and effect, and this fact alone produced a most significant intercrossing between peoples evidently identical in origin. Thus, the whole mass of physiological phenomena, considered as characters, add one more proof in favour of the monogenistic theory. A few examples will suffice to justify these statements.
VI. Let us first prove that the duration of gestation is the same in all human races. The importance of this fact will be readily understood.
It is generally known that the intra-uterine life presents a notable disparity in the same zoological group, and sometimes in nearly related species. If men constituteda genus, it would be very strange if they were exempt from this law, and that no differences should have been observed, as they certainly would have been, between groups. These differences may indeed exist to a certain extent without rising to a specific character, for they are observed in our races of domestic animals, where they appear to bear some relation to stature. Gestation lasts sixty-three days in large races of dogs; from fifty-nine to sixty-three in the small. This is the period observed in menageries for the gestation of the jackal, the wild stock of the dog. But it rises to something over a hundred days for the wolf, however nearly related it may morphologically be to some canine races.
The period of lactation is very variable as to duration in different human peoples. Without even going beyond France, we should have no difficulty in giving examples of such differences, in which the maximum would almost double the minimum. It is evident that in this case manners, customs, etc., play the most important part, and that the question of races scarcely enters at all. With the Negroes, lactation lasts, as a general rule, for two years, and the period is quite as long in all oriental populations. It lasts for five years inChina. But as M. Morache tells us, the Chinese mother only prolongs it in order to retard the recommencement of the monthly courses, which, in this fertile race, is rapidly followed by a fresh pregnancy. There is nothing surprising in the possibility of such prolonged lactation. It is generally known that the secretion of the milk is supported by its use. Amongst ourselves, according to the evidence of Desormeaux, one nurse will sometimes suckle three or four infants in succession.
VII. The period of suckling is followed by that of childhood, a condition very distinct from those by which it will in turn be followed. The human being is as yet neither male nor female. The first manifestation of sex is one of the most important epochs of life, and it is interesting to observe that the arrival of this epoch varies within very wide limits.
The female, on account of the phenomena to which she is then subject, and which admit the possibility of direct observation, is, in this case, specially adapted for the researches of the anthropologist. Now, taking extreme numbers, obtained by different observers upon several peoples of the globe, we find that the minimum age at which the female becomes pubescent is that of eight to nine years, as observed by Oldfield in the Eboes, and the maximum age, that of eighteen to twenty years, noticed by Rush, among some tribes of North America. Setting aside these exceptional numbers, we find as general extremes, ten to eleven years on the one hand, and fifteen to sixteen on the other.
The variation we see is great, and we are naturally led to ask if it is at all constant in human groups. The numerous statistics which have been collected upon this subject, seem to justify us in giving an absolutely negative reply to the question.
And, in the first place, there is no doubt that hereconditions of lifeplay an important part. From the researches of M. Brierre de Boismont, it appears that, in the same locality, the higher or lower social position, and the consequentdifference in mode of living, produces an average variation of fourteen months. In Paris, the women of the lower classes are pubescent at fourteen years and ten months, those of the middle class at fourteen years and five months; those of the upper class at thirteen years and eight months.
The mode of life is sufficient to produce differences of a very marked character in the age at which the female becomes capable of conception. At Strasbourg, as at Paris, the young country girl is behind those of the town. The difference is about 8½ months for Strasbourg and 4½ for Paris. In Alsace, as upon the banks of the Seine, the hardships of field labour render the functions of the individual life more active at the expense of those connected with the sexual.
Again, we cannot doubt the influence which is certainly exercised by temperature. M. Raciborski, adding to his own investigations those of a large number of other medical men, has even thought himself justified in drawing the conclusion that the age of puberty is advanced or retarded by a little more than a month for each degree of latitude, according as we calculate from the equator or the pole, with the condition only that the temperature increases or decreases with the latitude.
The action of the three causes I have just mentioned are most evident. But, as we have already remarked, food, temperature, and even mode of life do not alone formconditions of life. Many other influences besides these act upon the organism. The greater or less amount of light, and of actinic rays, cannot be without effect.
All these influences explain how it is that the age of puberty varies with the habits in the same race; how women, belonging to the same branch of the white aryan race, may present the extremes which I have alluded to above. From among the latter the Swedes and Norwegians are pubescent at from 15 to 16 years; the English at from 13 to 14; but the English Creoles of Jamaica at from 10 to 11 years. At Antigoa, Negro and White women, transported into the samecommon conditions of life, no longer present any difference in this respect. We see also how it is that women belonging to the most different populations and races, Swedes, Dacotas, Corfiotas, Potowatomies, English, and Chinese, become pubescent at the same age.
Does then race stand for absolutely nothing in the physiological phenomena under consideration?
Some facts seem to authorize us in holding a contrary opinion. The Esquimaux women of Labrador are as forward in this respect as the Negresses of our colonies. In the Potowatomies (Algonquins) and the Dacotas (Sioux) there seems to be an average difference of a year in the appearance of the first phenomena of puberty. Several other observations of the same nature might be quoted from various travellers. There is, however, nothing to astonish us in these facts. They are only the reproduction in the human species, of what we observe every day in our domestic animals and cultivated plants, all of which have forward and backward races.
M. Lagneau studied this question with particular reference to France. He came to the conclusion that the conditions of life are not sufficient to explain the differences which were proved by his investigations, and that the age of puberty, depending upon the rapidity of the development of the organism, varies slightly with the race. This opinion, which it seems as if we might accept within the limits he himself has prescribed, M. Lagneau states with great reserve.
These limits are very narrow. They vary from fourteen years and five days to sixteen years, one month and twenty-four days. The minimum age is presented by the female population of Toulon: the maximum, by that of Strasbourg. But between these two localities there is a difference of about three degrees of latitude and five degrees in the mean temperature. Toulon enjoys a very equable climate; the climate of Strasbourg is, on the contrary,excessive; at Toulon the climate is sunny, while at Strasbourg there is much cloud; theToulonaiselives in the open air, andbreathes the stimulating air of the sea, theStrasbourgeoiselives in the house and breathes an air which is generally damp; the former drinks wine, the latter beer. All these conditions, stimulating on the one hand, and debilitating on the other, must exercise some influence. After taking all these circumstances into consideration, we see that, in France at least, the influence of race scarcely exceeds that exercised by difference in social position upon the population of the same town.
The researches of M. Lagneau also have reference to the time when, both in the male and in the female, the reproductive faculties become extinct. The evidences are here neither so numerous nor so definite. Nevertheless, from the little that we know on this point, the result would seem to point to conclusions similar to those which we have mentioned above.
VIII. We might easily be led to think that forwardness or backwardness in organic development, defined by the age at which puberty appears, should involve a proportionately longer or shorter duration of human life. Precise observations are far from being so numerous and complete as to solve this important problem with any degree of certainty. The greater number of facts with which we are acquainted, scarcely seem, however, to support the theoretical conclusions admitted by some anthropologists, by Virey among others. Everything seems to indicate, on the contrary, that the limits of life are almost the same for all human races,provided thatthey are placed in conditions of existence, which arerelativelyequally favourable. It is, in fact, evident that these conditions exercise a most marked influence upon the duration of organisms. When life is in question we do not deny theaction of the conditions of life.
Here, again, appears the multiple nature of these conditions. We find from the statistical researches of Boudin that in sixty-seven years, from 1776 to 1843, the average life of man in France was increased by eleven years. It has, therefore, gained sixty days a year; it has attained almostthe highest limit gained in this respect by European peoples (34·45 years). The temperature has not changed, nor has there been any amelioration in the climate. But the general conditions of existence are modified and the result appears in these very significant figures.
The average life of European Whites, the only peoples concerning whom we possess sufficiently exact data, oscillates between 28·18 years (Prussia) and 39·8 years (Schleswig-Holstein, Lauenbourg); a difference of more than eleven years.
The tables of average duration of life, collected by Boudin and borrowed from Hain and Bernouilli, prove beyond a doubt that, amongst our European peoples at least, mean duration of life depends to a very slight extent, if at all, upon the race. The German states present an average of from 28·18 years (Prussia) to 36·8 years (Hanover).
Temperature, at least when considered alone, seems to exercise hardly any notable influence, Naples standing almost midway between the preceding numbers (31·65 years).
These facts, obtained from among the best known peoples, justify us in thinking that,other things being equal, the duration of life must be almost universally the same. It will be understood that all strict comparison is here out of the question, for want of statistical documents, properly so called. Still, a number of facts obtained by various travellers amongst peoples of very different races, and, in some cases, placed under opposite conditions of existence, seem to justify this conclusion.
All travellers, who have been in a position to judge for themselves, have spoken of the Lapps as generally living to a great age; men of from seventy to ninety years are not rare amongst them.
Upon the evidence of travellers of the highest reputation, it seems that the greater number of American peoples also reach an advanced age, and often without bearing any external traces of decrepitude. However rude and often precarious their mode of life may be, the representatives ofthese races are in no way inferior to Europeans, as regards duration of life.
Is it different in the case of the Negro, as Virey has thought? Everything seems to prove the contrary. Even when removed from his native land, and placed under conditions which we have seen to be very unfavourable to him, the Negro lives as long as the European. This result is obtained from the register of slaves consulted by Prichard in the West Indies. This anthropologist has shown, by examples drawn from different sources, that centenarians were far from rare among the individuals of this race scattered through different parts of America. From the documents which he quotes, it even appears that in the States of New Jersey, an official census gave a little more than one Negro centenarian in the thousand, but only one White centenarian in one hundred and fifty thousand.
Nevertheless Adanson, Winterbottom, and others, state that the Negro of the Senegal and Guinea age early in life, and the latter adds that individuals of this race rarely reach an advanced age. Dr. Oldfield, in the great English Expedition up the Niger, makes the same remark with reference to the part of the country which skirts the river Nunn, a marshy region, covered with a luxuriant vegetation supported by inundations. But higher up the river, in the country discovered by Nyffé, he met, on the contrary, with a large number of old men who must have been upwards of eighty, and visited an old chief, who, he says, was 115 years old.
There is nothing contradictory in these facts. They merely show us that the Negro is subject to the law common to all other men. It is in vain that he has conformed to conditions of existence, which the White has so much difficulty in living under; when these conditions are aggravated and exceed a certain limit, he suffers, and his life is shortened. The native of the banks of the Nunn is placed,as a Negro, under conditions of existence similar to those to which, in former times, theWhitesof the Dombe in France were subject, and in both cases the result was the same.
But beyond these exceptional localities, when the conditions are equally favourable, the duration of life seems to be the same in the two typical races which are the most widely separated of all in the human species. In any case the same extreme limits have been proved for the Negro and the White.