Pedagogical Anthropology by Maria Montessori (best novels of all time TXT) ๐
Read free book ยซPedagogical Anthropology by Maria Montessori (best novels of all time TXT) ๐ยป - read online or download for free at americanlibrarybooks.com
- Author: Maria Montessori
- Performer: -
Read book online ยซPedagogical Anthropology by Maria Montessori (best novels of all time TXT) ๐ยป. Author - Maria Montessori
This fact is further confirmed by Wagner's figures, cited by Broca:
MEAN WEIGHT OF THE BRAIN
(According TO Wagner)
Here again we have a false maximum at twenty, which nature subsequently corrects through mortality.
From such knowledge we obtain certain important rules of hygiene.
The normal brain which exceeds the common limits of volume is not, in an absolute sense, incompatible with life. We need only to call to mind certain men of genius who had the brains of a giant.
Accordingly a brain which exceeds the limits demands of the individual who possesses it that he shall live according to certain special rules of hygiene. Children and young people who are too intelligent, too good, in other words, children of the elite class demand a special treatment, just as much as any other class of beings that pass beyond the bounds of average normality. Parents and teachers ought to be enlightened in regard to these scientific principles; the growth of individuals who are exceptional in regard to their intelligence and their emotions, should be supervised as though it were something precious and fragile. Such individuals are destined to be more subject than others to infective maladies, which frequently prove fatal, developing symptoms of meningitis and cerebral affections. Consequently a hygienic life, psychic repose, an avoidance of emotional excitement, moderate physical exercise in farm or garden, a prolonged stay in the open country, might be the salvation of children of this type, who often are over-praised and over-stimulated by friends and relatives, and consequently subjected to continual excitement and surmรฉnage to a degree destructive to their health.
Extreme Individual Variations of the Volume of the Brain.โIn regard to individual variations, the authorities give various figures, from which the following have been selected as most noteworthy for their accuracy of research:
NORMAL EXTREMES OF INDIVIDUAL VARIATIONS IN THE VOLUME OF THE BRAIN
Authors Age: from 20 to 60 years From 60 to 90 Maximum Minimum Maximum Minimum Calori 1,542 1,024 1,485 1,080 Bischoff 1,678 1,069 1,665 1,080 Without distinction of age: Broca Maximum1,830 Minimum
1,049
These figures refer to individuals belonging to European races.
Comparison with the Brains of Apes.โThe brain of the great anthropoid apes (Chimpanzee, Orang-utan, Gorilla), whose total weight of body is comparable to that of man, weighs on an average 360 grams, and the greatest weight which it can attain is 420 gr.
Specific Gravity of the Human Brain.โIn normal individuals, the average specific gravity is 1.03; in insane persons it is slightly higher: 1.04.
The Relation between the Weight of the Brain and the Cranial Capacity: Figures given by Lebon:
Weight of the brain in grams Cranial capacity in cubic centimetres 1,450 1,650 1,350 1,550 1,250 1,450 1,150 1,350Figures given by Manouvrier:
Weight of the brain in grams Cranial capacity in cubic centimetres 1,700 1,949 1,450 1,663 1,250 1,432 1,000 1,147Increase in the Volume of the Brain.โStudies regarding the growth of the head, although not yet complete, have gone sufficiently far to give us some useful ideas. In regard to the volume in a general sense, the cranium in its growth obeys the cerebral rhythm.
We shall speak in the section on Technique of the methods of measuring the head: at present it will suffice to point out that the measurements may be made directly upon the cranium, and the cranial capacity calculated directly from the head: and that the maximum linear measurements are sufficient to indicate the volumeโsuch measurements being the three maximum diameters, longitudinal, transverse, and vertical, and the maximum circumference. Even the forehead, as an index of the general volume of the brain, is of interest in researches relating to the volumetric growth of the head.
Regarding the growth of the several cranial dimensions, the most accurate and complete knowledge is furnished by Binet's researches among the school-children of Paris (1902).
This author has made special investigations into the rhythm of growth of the cranium and of the face, with special reference to the period of puberty. The following are the mean averages obtained by him, relative to the three diameters corresponding to the three maximum dimensions of the head:
MEAN AVERAGES OF CEPHALIC MEASUREMENTS TAKEN UPON CHILDREN OF DIFFERENT AGES
(Binet: From the schools of Paris)
It is evident that these figures contain inaccuracies, especially in regard to the vertical diameter (where the subsequent two-year period gives a smaller measurement than the preceding) due to the fact that the averages were obtained from an insufficient number of subjects or from subjects differing too widely in intelligence (from schools of different grades). For this reason Binet summarises the differences in growth, that is, the increase in relation to the diameters, under broad groups (six year groups, from four to ten years, and from ten to sixteen), in order to determine whether puberty exerts a sensible influence upon the cranial growth. The result is contained in the following table:
INCREASE OF THE THREE MAXIMUM DIAMETERS OF THE HEAD IN MILLIMETRES FROM FOUR TO EIGHTEEN YEARS OF AGE
Age in years: from โ to โ 4-6; 6-8; 8-10 10-12; 12-14; 14-16 16-18 Antero-posterior diameter 5.6; 0.8; 2.4 4.4; 1.8; 5 2.1 8.8 11.2 Transverse diameter 1.1; 3.3; 0.7 2.2; 3.9; 0.5 4.4 5.1 6.6 Vertical diameter 2.8; 0.4; 0.8 4.8; 2.3; 2.5 0.6 4.0 9.6From which it appears that there exists, in regard to the head, a puberal acceleration of growth.
These conclusions of Binet are indirectly confirmed by the researches of Vitale Vitali regarding the development of the forehead in school-children; since it is well known that the forehead represents the index of the general growth of the cerebral cranium.
Vitale Vitali based his observations upon school-children and students between the ages of ten and twenty. He not only measured the width of the forehead (frontal diameter; see Technique), but also measured its height, obtaining the percentage of its relation to the width (frontal index).
These are his figures:
FRONTAL INDEX AND DIAMETER ACCORDING TO AGE
(Vitale Vitali: Researches Among Scholars and Students From 10 To 20 Years Old)
Age Frontal index Frontal diameter Amount of increase 11 years 73.05 107.5 โ 12 years 74.11 112.0 4.5 13 years 74.14 112.5 0.5 14 years 74.80 114.4 1.9 15 years 75.67 116.8 2.4 16 years 77.24 120.1 3.3 17 years 77.02 120.6 0.5 18 years 77.36 121.5 0.9 19 years 77.60 122.8 1.3 20 years 77.15 122.1 0.7Accordingly, between the years of fourteen and sixteen there is a puberal acceleration of growth, accompanied by an elevation of the forehead (high frontal index).
Vitali gives, as extreme limits of the frontal index, 68 and 83.
But in order to give a better illustration of the author's figures, his own words may be quoted: "It appears from our observations that the forehead begins to develop in notable proportions during the fourteenth year, and that the development of the frontal region as compared with the parietal region continues to augment up to the sixteenth year; after this it still increases, but only by a few millimetres, until the end of the sixteenth year. The cephalic development is completed between the sixteenth and eighteenth years. This observed fact is of great importance in relation to the development of the intellect."
The most complete figures at the present time on the growth of the brain, are those of Quรฉtรฉlet, which follow its development from birth until the fortieth year. They are summarised in the following table:
INCREASE IN THE CIRCUMFERENCE OF THE BRAIN AND IN ITS THREE MAXIMUM DIAMETERS
(According to Quรฉtรฉlet)
It appears from the foregoing table that after the twenty-fifth year the growth of the cranium practically ceases in all directions. In regard to the rhythm of growth, the problem is rendered clearer by the following table, which gives the annual increase:
ANNUAL INCREASE IN THE MAXIMUM CRANIAL MEASUREMENTS IN MALES
(From Figures Given by Quรฉtรฉlet)
It appears from the above table that the total growth of the cranium takes place to a notable extent during the early years of life; as regards the diameters, the longitudinal diameter grows faster during the first few months than the transverse; but after the first year, the two maximum diameters which determine the cephalic index increase in very nearly the same proportion (constancy of the cephalic index throughout life). The vertical diameter on the contrary undergoes a relatively much greater increase than the two others, since, although much shorter than the transverse, it nevertheless overtakes and surpasses it in its absolute annual increase.
This corresponds to the fact that the first two diameters are indexes of growth relative to the base of the cranium, while the vertical diameter is the index of expansion of the cranial vault, which more directly follows the growth of the brain and elevates the forehead as it pushes upward.
Quรฉtรฉlet's figures, however, fail to show in the rhythm of growth that puberal acceleration which has been observed to take place in the growth of the brain. This contradicts the researches of Vitali and also those of Binet.
Similar studies have been made a number of times during the last few years, especially in America, but with English tables of measurement, and with little uniformity in the results obtained by the different investigators.
Among the most recent and most complete figures should be cited those of Bonnifay[38] in which however the measurement of the vertical diameter is lacking, or in other words the third element needed, in conjunction with the dimensions of length and breadth, to give the volumetric factors.
CRANIAL MEASUREMENTS AT DIFFERENT AGES
(According to Bonnifay)
Among the linear measurements of the cranium, the one which serves to give the most exact index of volume is the maximum circumference.
This index, nevertheless, is not a perfect one, in the same sense that the stature, for instance, is a perfect index in respect to the body, because in the case
Comments (0)