The majority of observers find the most rapid growth in height from fourteen to fifteen. This is especially apparent in the latest, and in some respects, the most satisfactory, measure- ments, because all were made on the same lOO boys from thir- teen and one-half to eighteen,^ living under uniform conditions in a military school.
Burk has massed, from some of the data cited, the weights of 24,500 children of Boston, 34,500 children of St. Louis, and 9,600 children of Milwaukee, making 69,000 in all, in such a way that at each age the number of children from each city has been proportionately represented in the result in the following table: Table H Boys.
Girls.
Age.
Average for each age. Pounds.
Absolute ^ annual increase. Pounds.
Annual increase. Per cent.
Average for each age. Pounds.
Absolute annual increase.
Pounds.
Annual increase. Per cent.
N. V. Zak,2 e. g., measured the height and chest girths of 1,434 pupils of Moscow Real-schools and 2,811 from classical gymnasia.. He finds that height decreases during the day slightly at eleven, much more at fourteen, and less at eighteen, while weight increases also most at fourteen. At every age * P. Godin. La Croissance, pp. 224, Paris, 1903. His results are more fully discussed in the next chapter.
' In a volume in Russian, entitled Physical Development of Children in the Secondary Educational Institutions of Moscow. 1892, pp. 271. The chief points and tables have been translated for me by M. de Perott.
GROWTH IN HEIGHT AND WEIGHT 9 these boys are markedly taller than peasant boys. The pubertal increment of growth in height at from thirteen to fourteen is more rapid than that of English, Swedish, or Boston boys, but 87 66 65 64 03 62 61 00 59 57 55 53 51 49 47 45 43 A W ■d s s i 1 1 g a o 0.
s Boys Girls 10 THE PSYCHOLOGY OF ADOLESCENCE the decline of rate from sixteen on is most marked yet with a tendency to resume growth at twenty-one. Up to eighteen, the more years had been spent in school the greater the average height. The yearly increase in height fell off from nine to ten, and then slowly increased, reaching a marked maximum from thirteen to fourteen, and thereafter falling off more rapidly than it rose. Puberty began from one and one-half to two years earlier among the gymnasiasts than among the rural popula- tion, and Jewish boys began their increase in height earliest, and from thirteen to fourteen exceeded all others in rate, but were then overtaken by the Orthodox Russians, whose yearly increment thereafter exceeded to eighteen or nineteen.
Prince N. W. Viasemsky,^ on measurements embracing 4,872 individuals, not only found periods of acceleration alter- nating with those of retardation, but thought the latter charac- teristic of the period of the development of the reproductive organs, which modify profoundly the equilibrium between assimilation and expenditure of energy. He conceived puberty as an acute crisis, and that bad heredity tended either to prema- turity or retardation, as well as to intermittence. School had no influence upon those who were robust, but for the feeble it was helpful in approximating their manner of growth to that of those who were strong, or making it more regular. On the whole, he thought school retarded puberty, and also that a period of arrest was compensated by one of more rapid growth. He also found that, while there existed a certain correlation be- tween different measurements, it was of a purely individual character and could not be expressed by any general formula, and that in his physical proportions man did not acquire his true type until this stage of life. The age of eighteen, he found unfavorable and critical in the development of the human organism, generally involving arrest and diminution of activ- ity, as if the energies of growth were exhausted and needed reparation.
In Europe height and weight have been determined in most of the leading countries for yet larger numbers: In ^ Ismenenia organisma v periode sformirovania, or modifications of the organ- ism during the period of puberty from the age of ten to twenty. 278 tables. 43 diagrams. St. Petersburg, 1902.
GROWTH IN HEIGHT AND WEIGHT II England, for over 40,000;^ in Denmark, on 17,134 boys and 11,250 girls; ^ in Freiberg, on 10,343 boys and 10,830 girls; ^ in Sweden, on 15,000 boys and 3,000 girls;* in Saalfeld, on 4,699 boys and 4,807 girls;^ in Moscow, on 3,212 boys and 1,495 gi^ls; ^ in Turin, on 1,048 boys and 968 girls ^ in Lau- sanne, on 2,000 children;^ in Hamburg, on 515 boys;^ in Gohlis, on 1,386 boys and 1,420 girls.^^ These references might be indefinitely extended.^ ^ Unless we except the unscientific effort of Lange,^^ whose data include various races for height with little discrimina- tion, and are not worked up according to the scientific meth- ods of modern statistics, there has been no attempt to mass the measurements of all these 138,224 children, and indeed, this would have still less value than the above totalizing of returns from different American cities, on account of the still wider diversity of race and conditions.
' Report of the Anthropometric Committee of the British Association for 1883, Francis Galton; and Manual of Anthropometry, Charles Roberts. London, 1878.
* Report of the Danish Commission, Axel Hertel.
' Die GrOssenverhaltnisse der Schulkinder im Schulinspektionbezirk, Arthur Geissler und Richard Uhlitzsch. Freiberg, Zeits. des K. Sachs. Statistischen Bureaus, vol. xxxiv, 1888, pp. 28-40.
* Laroverkskomitens Betankande IH. Bilage E. Redogorelse for den hygieniska undersokningen afgiven af komitens ledamot Axel Key. Stockholm, 1885, i, p. 528, with appendix of several hundred tables and curves. Condensed by Burger- stein. Schulhygien. Untersuch. Leipzig, i88g.
'' Die Korpergrosse und das Gewicht der Schulkinder des Kreises Saalfeld, Emil Schmidt. Archiv f. Anthropologic, vol. xxi, 1892-93, pp. 385-434.
* Die Schulhygiene auf der Jubilaumsausstellung der Gesellschaft ftir Befdrde- rung der Arbeitsamkeit in Moskau, Fr. Erismann. Zeits. f. Schulgesundheitspflege, ' Die Entwickelung des Menschen in den der Geschlechtsreife vorangehenden spateren Kinderjahren und in Jiinglingsalter von 7 bis 20 Jahren, Pagliani.
^ Korperlange und Wachstum der Volksschulkinder in Lausanne, Combe. Zeits. f. Schulgesundheitspflege, 1896, pp. 569-589.
* Die Korperverhaltnisse der gelehrten SchUler des Johanneums in Hamburg, L. Kotelmann. Zeits. des K. p. s. Bur., 1879.
^^ Messungen von Schulkindern in Gohlis-Leipzig, Arthur Geissler. Zeits. f. Schulgesundheitspflege, 1892, pp. 249-253.
'^ Consult on the whole question of growth in height and weight the admirable article and bibliography of Burk, Am. Jour, of Psychol., vol. ix, p. 315 ef seq.
" Die normale KorpergrSsse des Menschen, Emil von Lange. MUnchen, 1896. He has also constructed a somewhat elaborate Skala-Messtabelle for use in families and schools to show the variations within what he deems normal limits from birth to the twenty-fifth year.
12 THE PSYCHOLOGY OF ADOLESCENCE From birth to three and one-half, and indeed up to five years, or the beginning of school life, we have measurements on rela- tively very few children. Toldt and Hecker are still our standards for length, and Schroder and Fehling for weight, during prenatal stages. While there have been many meas- urements at birth, Quetelet and Zeissing, Camerer, Dafner, and Schmidt-Monnard, the former based on only ten of each age and sex, and all on but very few, are our only authorities for growth during the first and second years. So, too, most of the studies of large numbers stop before the last stages of growth, for which we are perhaps still further from having reliable norms. The English commission and Pagliani began at three and one-half, Peckham at four and one-half. Bow- ditch, West, and Roberts at five and one-half, but most begin at six or seven, soon after the age of entering school, and at thirteen and one-half some of the most important of these measurements end. From the middle teens on to maturity there are far fewer numbers, so that data begin- ning for the pre-adolescent increment and the preceding low- ered rate of growth are based on the largest numbers. Combe, Geissler, Uhlitzsch, and Landsberger stopped at thir- teen, Carstadt and Hertel at sixteen, Gilbert and Erismann at seventeen, Bowditch and Peckham at eighteen, PagHani, Porter, Kotelmann, Key, and Quetelet at nineteen or twenty. Those that continued weighed and measured small numbers, and even at eighteen results begin to be uncertain, while after twenty they become not only increasingly variable, but some- times contradictory and even anomalous, some even suggest- ing a shortening of stature or else early mortality among tall people. Baxter's ^ study of over a million recruits, on the other hand, actually indicates an increase up to thirty-four.
From the standpoint of modern statistical theory, not only the methods of massing large results, but many of the more comprehensive studies of height and weight leave very much to be desired. There is often lack of uniformity in taking measurements, especially where this is done by teach- ers. Age determinations are often too inaccurate, and fre- quency of measurements vary. It makes a great difference * Statistics of the Provost-General's Bureau, 2 vols., Washington, 1875.
GROWTH IN HEIGHT AND WEIGHT 13 also whether measurements through the successive years are taken upon the same or upon different children. As Boas, perhaps our best American authority on the treatment of these statistics, points out, " the younger groups contain many individuals who will not reach the adult stage, while the older classes contain only few individuals, who will die before becoming adults." Those who are remote from the average, whether too large or too small, approach pathological condi- tions and so are more likely to die, and where their measure- ments are included variations are greater, as is illustrated in the curious decrease in brain weights of males after twenty, due to the exceptional mortality of those with very large brains at about this age. Again, statistics of large numbers contain more of the poorer classes who are smaller at the same age, and among whom there is greater mortality, while the more favored classes found in high schools and colleges are larger. Perhaps, again, weak or small children go to school longer than those that are strong, or stay longer be- cause more slowly promoted, so that the older school children will include an undue proportion of those who are dull and have been sickly. Again, if many children of slow growth should die during adolescence, this might affect the overlap- ping of the curves of boys and girls, for the amount and dura- tion of the latter's superiority is smaller, the more favorable the conditions of life. Once more, there is a wide difference be- tween a mean and a type. Children of the same racial stock, like, for instance, the tall Swedes, represent a type, as would the smaller Italians or the yet smaller Japanese, but the mean of the two races might find its analogue in an average between dogs and horses which would represent no individual. Every generalization of heterogeneous persons suppresses facts con- cerning individuals, and to seek a cause for every variation from an average is folly. A type, on the other hand, is a norm to which every individual in a really homogeneous group tends to approach or to vary from, and in a pure race the average persons should be most frequent, and around them others should be grouped closely as well as symmetric- ally. Any individual, although far from a miscellaneous average, may represent a type and illustrate some tendency away from the average in some new direction, or may even be a 14 THE PSYCHOLOGY OF ADOLESCENCE sport leading to a new type. Still again, race, climate, pov- erty or riches, which are known to cause difference for the •same age, would almost violate the law of social type; and the theory of least squares has suggested many more or less complicated and interesting modes of treating statistics to determine their real significance so as not only to present, as e. g., by percentile grades, but even to evaluate, the dif- ferent degrees of departures from the mean.
It is not strange, therefore, that some of the most valuable measurements are those made upon a single child or upon a very few. This method is perhaps best illustrated by Weiner's ^ measurement of the height of each of his four sons from birth to the age of twenty-five years. In the graphic illus- tration of these results on the opposite page, A represents the growth curve of the three older sons, and B the absolute annual increase; the heavy line is the oldest, the light the second, the dotted the third son; figures on the left apply to curves A, and on the right, to curves B. The fourth son, by a differ- ent mother, taller and older than the first, follows a different curve in both height and weight.
Camerer,^ too, has studied his own children, and with the most exact methods, to determine their metabolism, although his best work has been done on infants. Landsberger,^ fol- lowed a few boys for seven years.
It is, however, quite remarkable that whether individuals or large groups are studied, the main characteristics of the curves of growth remain the same for both height and weight, so that we have the following established results: first, as shown in every study since Quetelet, a marked pre- pubescent acceleration in both height and weight; second, precedence of girls in this accelerated growth by a year or two; third, a period of slightly diminished growth centering about the ages from eight or nine to ten or eleven; fourth, a gradual and probably irregular tapering off of growth in height at about eighteen or nineteen, and to a degree, of * Das Wachstum des menschlichen Kftrpers, Christian Wiener. Karlsruhe, 1890. ^ Untersuchungen liber Massenwachsthum und Langenwachstum. Jahrb. f. Kinderheilkunde, 1893, pp. 249-293.
2 l6 THE PSYCHOLOGY OF ADOLESCENCE Bowditch ^ found that the relation of weight and height in growing children is such, that at heights below 58 inches, boys are heavier than girls in proportion to their stature; at heights above this, the reverse is the case. By a supplemen- tary application of Galton's methods to his data still later, he found that the period of pubescent acceleration of growth occurred at an earlier age in large than in small children, or that large children achieve their most rapid growth at an earlier age than small ones; that this growth period differs in larger boys from that in small boys in duration rather than in intensity, and that in girls this difference is not apparent. He also found that at eleven there is a remarkably slow growth in weight and height in both girls and boys, less, in fact, than for several years preceding or subsequent to it, and that in girls a similar but less marked period of retarded growth occurs at nine, but the rate of increase in weight decreases less. The period of female superiority in height was found to be less in tall than in short children, while the female superiority in weight was found to be more marked in heavy than in light children. The author concludes by desiderating annual measurements of not only growth but strength, especially during adolescence, besides annual school examinations, not only the purpose of recording power and size, but to find whether pupils are progressing physically under the environment of instruction, regime, etc.
The Milwaukee studies led to the conclusion that boys are taller till the twelfth and heavier till the thirteenth year, but from thirteen to fifteen girls are both taller and heavier; that after fifteen boys exceed in both weight and height, and that girls almost cease to grow at seventeen.
Key found that Swedish boys grow rapidly in the seventh and. eighth year. From the ninth to the thirteenth year their rate of growth diminishes, and they may reach almost a standstill at the tenth year, which falls about midway be- tween two periods of growth acceleration. The curve of in- crease at the fourteenth year is steep and for height, con- * Boston Med. and Surgical Journal, October 19, 1872.
• The Growth of Children studied by Galton's Percentile Grades, by H. P. Bowditch. Twenty-second Annual Report Mass. State Board of Health, 1890, pp.
GROWTH IN HEIGHT AND WEIGHT I?
tinues through four years, reaching its maximum at the fif- teenth and ending with the seventeenth year. Weight increases during all this period, but at first not so fast, and reaches its maximum of rate at the sixteenth year, or one year later than the fastest growth in height. Swedish boys grow heavy fastest in the sixteenth and through a part of the seventeenth year. At seventeen, and on at least to twenty, boys grow in weight more than in height. At eighteen the curve of growth decreases rapidly to a much slower rate. Key's results showed that schoolboys pass through three distinct periods of growth: a moderate increase in the sixth and seventh years, a weaker growth from the ninth to the thir- teenth year, and a much more rapid increase in height and weight from the fourteenth to the sixteenth year. The growth of his girls is also periodic, but comes a few years earlier than that of boys. Swedish pass American boys in height and weight in the nineteenth year. The period of growth begins earlier with the well-to-do than with the poorer classes, but is more rapid when it does come, with the latter. The period of diminished growth for girls is like all the other stages, earlier and less marked. Their year of min- imum growth is nine. The great acceleration in growthrate for height begins at the tenth year in Swedish girls from well-to-do families and lasts five years, reaching its maximum at the twelfth, or three years earlier than with boys. At fif- teen the curve of growth falls, first slowly and then rapidly, and at seventeen nearly reaches zero. Growth in weight begins at twelve and lasts four years with the maximum at fourteen, which is the year of most vigorous growth in girls. Weight continues to increase rapidly during the seventeenth year, and sinks nearly to zero at twenty, when girls seem to have reached nearly the limit of their physical development. The first menstruation appears from one to two years after the maximum growth in height. For both sexes growth in height precedes that in weight. The superiority of girls over boys in both height and weight lasts five years, or from the twelfth to the seventeenth year, which is much longer than other observers have found. Danish girls, according to Her- tel, increase in height most rapidly from twelve to fourteen, and boys from thirteen to sixteen; and in weight, girls increase 3 1 8 THE PSYCHOLOGY OF ADOLESCENCE most from twelve to fifteen, and boys from about thirteen to sixteen or seventeen, and before and after growth is less rapid.
There is much consensus among investigators that from eleven (Bowditch, Geissler, Uhlitzsch, Combe) or twelve, (Key, Hertel) till fourteen (Combe) or even sixteen (Key, Hertel), girls are taller than boys and are then overtaken by them. This is by some thought to be true of all races and classes of society. Only Lange, Quetelet, Liharzik, and Wiener, all of whom measured small numbers, think that in length of body girls remain always behind boys of the same age. Lange points out that the period of excess of girls over boys has been most marked by observers who have studied the hard-working classes, and that it may be excep- tional if not abnormal and can not be called as yet estab- lished independently of mode of life and social station. While on the whole, the evidence seems to us to point pretty clearly to a more or less prolonged superiority of girls, the question as to whether they actually exceed boys is of much less import than that they have a period of rapid increment and that it precedes that of boys.
Only Quetelet, writing before modern refinements of method and dominated by mathematical theory, who, as we saw, measured only ten individuals of each sex for each year, failed to note this sudden outburst of growth in height or weight. It is, however, not only demonstrated by all careful studies within the last thirty years and patent to common obser- vation, but it is found in savage man and has been observed in several species of animals. Prof. C. S. Minot tells me he noticed this in his elaborate weighings of guinea- pigs,^ in which puberty occurs at the age of about four months. A much less marked post-pubertal retardation was also noticed. Prof. C. F. Hodge tells me he has noticed the acceleration in dogs, and Dr. Stewart also found it in rats and squirrels. Prof. A. H. Yoder, who weighed white rats daily for a long time, writes me: " I found they grew about three to four days and then rested about the same time. I also found there was an acceleration of growth at puberty.
* See also his Senescence and Rejuvenation, p. 133.
GROWTH IN HEIGHT AND WEIGHT 19 Besides physiological changes, the hair grows coarse and is often slightly tinged with brown, and there is a noticeable change in the motions and general appearance." Moon believes that " a corresponding fact is true in regard to horses and some other quadrupeds," and compares boys to Indian corn, which grows most in height when it " shoots and tassels," or reaches its age of puberty.
Of all single measurements, height is the most valuable. It is easily taken, is relatively constant, and not liable to much fluctuation. Along with weight it is the truest expres- sion of the energy of growth, the best index of health, and gives a datum from which, by the use of current norms and standards, many other data can be approximately inferred. It is, moreover, the most distinctly human dimension, as man alone has assumed a fully erect attitude. Some anthro- pometrists think growth in height to be more or less antag- onistic to growth in girth. Hall ^ formulates the following law: " When the vertical dimension of the human body is undergoing an acceleration of its rate of growth, the hori- zontal dimensions undergo a retardation of their rate of growth," and conversely. The two certainly vary independ- ently, and excess of either may tend to arrest of the other. Height is usually quite complete before twenty-five, while weight may augment indefinitely afterward, and during the years when both are increasing, each appears to have its own season, and the maximum of one more or less coincides with the minimum of the other. Weighing, on the other hand, gives no index of qualitative change. Decay in the most important tissues may be compensated by fat or water, and weight may increase from imperfect elimination of waste. Height once attained can not be reduced save by the slight intervertebral compression of cartilage and muscle, relaxa- tion of fatigue restored daily (more than half an inch, as Bishop and Bradford found by recumbency at night), and by old age; but weight is subject to diurnal and seasonal fluctuations and may be reduced fifty per cent by disease and regained, * W. S. Hall. Changes in the Proportions of the Human Body during the Period of Growth. Jour, of Anthropol. Inst, of Great Britain and Ireland, 1895, 20 THE PSYCHOLOGY OF ADOLESCENCE the brain, e. g., in progressive starvation remaining about as little diminished as the bones. Most tissues, however, are subject to many changes and increase slightly in weight with age, as the proportion of solid to fluid matter is aug- mented.
Imperfect nutrition checks growth in weight more than it does in height, but whether growth in either of these dimen- sions is preparatory for and conditions growth in the other; whether spring growth in height conditions the autumnal thickening of the body more than the latter conditions the former; whether height is a more vital growth than normal weight; whether we have here two manifestations of one and the same energy, or whether the fact of independent vari- ability means that there are two distinct principles or tend- encies, we do not know. If the number of individuals of a given age is distributed over uniform intervals of height and weight, as by the method of percentile grades, it will be seen that the age of greatest growth coincides with that of great- est mean variation from the average size. Although the range of individual deviations from any mean is great, very large or very small persons in both dimensions are extremely rare, and there is a limit beyond which every deviation be- comes abnormal and unhealthful. In general, while growth in height is one of the most desirable expressions of vital energy, but few would deny that symmetry and proportion are of at least no less importance. Young people who grow very tall and fail to develop proportionately in thick-