Adolescence - Its Psychology and Its Relations to Physiology, Anthropology, Sociology, Sex, Crime, and Religion (1931)

By G. Stanley Hall

This book is based on the author’s Psychology, now in preparation, which should logically have been published first. The standpoint of the latter is roughly and provisionally indicated in Chapter X, with which it is hoped any reader with philosophic interests will begin. This point of view is further set forth in the last part of Chapter XVI, and some of its implications appear in Chapter XII, which should follow. That, recognizing fully all that has hitherto been done in this direction, the genetic ideas of the soul which pervade this work are new in both matter and method, and that if true they mark an extension of evolution into the psychic field of the utmost importance, is the conviction of the author. Although most of even his ablest philosophical contemporaries, both American and European, must regard all such conceptions much as Agassiz did Darwinism, he believes that they open up the only possible line of advance for psychic studies, if they are ever to escape from their present dishonorable capitivity to epistemology, which has to-day all the aridity, unprogressiveness, and barrenness of Greek sophism and medieval scholasticism, without standing, as did these, in vital relations to the problems of their age.

• Language: English
• Publisher: Read Books Ltd.
• Release date: Mar 23, 2011
• ISBN: 9781446545492

Book preview

CHAPTER I

GROWTH IN HEIGHT AND WEIGHT

Individual growth recapitulates the history of the race—Rate of prenatal growth in height and weight—Statistical methods—Prenatal growth in animals—Causes that favor and hinder it—Lessened rate at eight to twelve, also at seventeen and eighteen—Delay and compensation—Last stages of growth—Advantages of size—What is growth?—National differences—New genetic theories of retaidation and the period of increment—Augmented size and power of the human race—A later, higher, new story superposed on the older foundations now represented in boyhood.

THE beginning of individual life, or the age of zero for all sexed animals, is when the male cell penetrates the ovum. Their attraction for each other, which Maupas thinks a relic of the psychochemic tropism of agamic generation, is the biological basis, as the karyonomic rejuvenation thus caused is the goal of love in the ascending stages of life. By their fusion in impregnation these two master cells, the bearers of heredity, acquire the momentum of growth, which next to love is perhaps the most interesting and important fact in the world of organic nature and the key to most of its problems. The new tensions and dominants, to use the terms of Reinke and Morgan, thus set free and given definite direction, begin to develop a new individuality, to which the parental one, which now begins to wane, is subordinated. With ontogeny in successive generations the immortal germ plasm puts on mortality, somewhat as lost limbs in lower or tissues in higher forms of life are regenerated. The marvelous phenomena of impregnation, in which pleasure, which all creatures seek, culminates and in the interest of which beauty, spring-time, blossoms, ornament, courtship in the animal world, and all physical and psychic secondary sexual qualities and even the life and death of the individual find their key and motive, thus start the long series of anagenic processes that end in complete maturity.

As the germ-cell begins to increase in size, its mass or substance does so, of course, at a faster rate than does its surface, so that, since all nutrition must first be absorbed from without, a limit is soon reached, and either equilibrium or death by starvation must ensue. This result, however, is avoided by cell division which begins at the nucleus and proceeds by very complex processes, which cytologists have lately made great progress not only in tracing but even in explaining. The first division results in two smaller daughter-cells of equal size, each of which grows in bulk and weight but does not separate to form each a new individual, as do the primitive unicellular organisms, but divides again, so that their numbers tend to increase in geometrical ratio. These successive generations of daughter-cells which constitute the adult body are thus all descended from a single ovum, and frequency of cell division mainly determines the rapidity of growth. The rate of the latter is high when the generations of cells succeed each other rapidly, and low if the intervals between successive divisions are long. The number of cells thus, as Minot has pointed out,¹ depends ideally upon the number of generations, each division effecting in some degree a rejuvenation, and an individual or biad being simply a group of cells produced from a single egg.

In this process the individual in a general way repeats the history of its species, passing slowly from the protozoan to the metazoan stage, so that we have all traversed in our own bodies ameboid, helminthoid, piscian, amphibian, anthropoid, ethnoid, and we know not how many intercalary stages of ascent. How these lines of heredity and growth along which all the many thousand species, extant and extinct, these viatica of the holy spirit of life, the consummate products of millennia of the slow travail of evolution, have been unfolded, we know scarcely more than we do what has been the impelling force, or will to live, which seems so inexhaustible and insistent. Certain it is that the cellular theory needs to be supplemented by assuming, both in the organism as a whole and in the species, powers that can not be derived from the cells. Probably, too, the original cause of phylogenetic evolution was no inherent and specificnisus, but, as we know it, was due to a struggle for survival forced upon organisms by their environment.

The early stages of growth are telescoped into each other almost indistinguishably, so that phylogenetically the embryo lives a thousand years in a day, and the higher the species the more rapid relatively is the transit through the lower stages. This law of tachygenesis may perhaps be expressed somewhat as follows: Heredity, which slowly appears as a substitute for the external causes that have produced a given series of characters, tends to produce that succession with increasing economy and speed and also to become in a way more independent of the causes which originally determined it.

The human ovum, when ripe for impregnation, has a diameter of about 0.2 mm. Mühlmann¹ has averaged the four best measurements of the monthly embryonic growth in length. To find the prenatal monthly rate of growth in weight, he assumes Welcker’s² estimate of 0.00008 milligram as the weight of a red blood-corpuscle measuring 0.007 mm; then an embryo of the above size would weigh 0.00228 milligram. Assuming with Mühlmann 0.003 milligram as its weight, these results appear in the following table:

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Thus at the end of the first month we have the enormous growth in length of 3,650 per cent. If we except the third month, when there seems to be another considerable outburst of growth in length, the rate of increase is less, though with oscillations in the ratio of decline each month up to birth. Weight, according to the above table, increases from impregnation to birth 905,600,000 fold. Here, too, the law of progressive decline is clear. During the first three months, weight increases 400,000,000 per cent; during the next three, 5,182 per cent; and during the three preceding birth, but 252 per cent. Thus the new-born child is millions of times heavier than the ovum in which it started, while in the next twenty-five years the adult will become only about twenty times heavier than at birth. At the third month the cells must therefore have divided twenty-two times if we assume their size and weight equal. Such estimates, of course, are only approximate and more or less conjectural, but it is certain that the growth per cent steadily diminishes during each foetal month. It is as if the nourishment of some of the cells began to suffer very early, and this may perhaps be ascribed to their differing remoteness from nutritive material. On Roux’s hypothesis of a struggle for survival between the tissues, organs, and cells of the same body for the available food-supply, some have sought to explain even the development of cavities, folds, and divisions as due to atrophic degeneration of those cells far from the blood-supply. Indeed, Mühlmann goes so far as to say that there is no other cause in pathology for necrotizing processes, than imperfect nutrition. From Weismann’s premise that multicellular organisms are differentiated from unicellular by the fact of death, he infers that this latter is due to the symbiosis of the cells, and says the organism dies because it grows. Growth results in death, or is constantly digging its own grave. He also infers that the function of cells is determined by their morphologic position in an organism, that it represents nothing more than a phenomenon of growth, and that current teleological points of view are irrelevant. He even reaches the surprising conclusion that some of the chief structural parts of the body, such as the skeleton, muscles, and nervous system, are products of defective nutrition, and their growth is really a regressive accumulation of inferior products. Folds, constrictions, hollows, the separation of organs one from another, which are phenomena of growth, may thus be due to the abortion or non-development of cells which are beyond the reach of food. The difference of distribution of nutritive material also causes great variations in the rate of growth of the different organs after they are once differentiated. Thus growth develops their diverse functions.

At birth the child is cast like a shipwrecked mariner by angry waves on a strange and unknown coast, and finds itself in a new and rigorous climate. Instead of the conditions of fluid pressure equal on all sides, it is now in a stereometric world. Its nascent senses are assailed by new stimuli; the alimentary canal now comes into full function; the lungs are first inflated with a gasp, the occurrence of which is one of the most easily established and important medico-legal facts, connected, perhaps, with the characteristic first note of the human voice, which philosophers since Kant have variously interpreted as a sign of pain, a shout of triumph and joy, or a purely mechanical insentient automatism. It is not strange, therefore, that the new-born child rarely gains, and often loses weight during the first few days, small and especially prematurely born infants usually losing more than large ones. Indeed, with all these profound readjustments, the marvel is that the loss is not greater.

At birth the average and maturely born child, about 19 inches long, has a little over one-third the length of body it will attain when adult, but its weight must increase nineteen- or twentyfold. During the first year, it grows about nine inches in length and gains about thirteen pounds, or increases less than one-half its length, but much more than doubles its weight. In both respects the absolute gain of the first year is greater than it will be in any other year of life. During the second year the child should grow in height a trifle over five inches and gain four or five pounds, and by two and one-half years of age should have about one-half its adult height and nearly one-fifth its adult weight. From this point on to the prepubescent acceleration, which begins at eleven or twelve in girls and nearly two years later in boys, the percentage of growth in both height and weight is rather constant. There is perhaps a little increase at seven, and a certain and almost universal retardation, most marked about the tenth year, but extending over several years; this depression in the curve some have wrongly thought complemental to its elevation during the period of pubertal increase. Many children suffer slight and more or less prolonged diminution in both rates during dentition, while some show a retardation and others an acceleration, ascribed to the change of habits beginning with school life. At eighteen there is a decided abatement of the energy of growth and an increase of sickness, but one or two years later in boys, especially if under favorable conditions, there often comes a last period of increase, tapering off, some think, asymptoically, but generally with irregularities, a period imperfectly known but of the very greatest interest, to final height in the early twenties. Girls are usually slightly less than boys in both weight and height, and twins than single births. Despite Fasbender’s ¹ conclusions to the contrary, Boas finds that first-born children exceed those born later, first-born girls excel others from six to maturity, and first-born boys excel from five to fifteen, and perhaps later. The average superiority of the former is 10 mm. in height and 1.6 pounds, and that of the latter 7 mm. and 1.2 pounds.

A literature of some threescore very valuable memoirs and tabulations of human growth is now accessible,² to say nothing of a far larger number of miscellaneous records kept in schools, gymnasia, homes, institutions for special classes, etc. Boas has summed up more comprehensively than any one else averages for the rate of growth in height of American children, based upon five of the best special studies of large numbers, viz., in Boston,³ St. Louis,⁴ Milwaukee,⁵ Worcester,⁶ Toronto,⁷ and Oakland, representing in all, 45,151 boys and 43,298 girls. With a very slight modification of the age, these results are presented in the following table, which explains itself:

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The growth of 742 different Amherst students (classes 1885–1901) measured twice a year by Hitchcock, the American pioneer in this work, shows the following results for later years:

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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, measurements, because all were made on the same 100 boys from thirteen and one-half to eighteen,¹ 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:

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The results embodied in the above tables are graphically presented in the chart on page 9.

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 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 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 population, 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.

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Prince N. W. Viasemsky,¹ on measurements embracing 4,872 individuals, not only found periods of acceleration alternating with those of retardation, but thought the latter characteristic 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 prematurity 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 between 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 activity, 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 England, for over 40,000;¹ in Denmark, on 17,134 boys and 11,250 girls;² in Freiberg, on 10,343 boys and 10,830 girls;³ in Sweden, on 15,000 boys and 3,000 girls;⁴ in Saalfeld, on 4,699 boys and 4,807 girls;⁵ in Moscow, on 3,212 boys and 1,495 girls;⁶ in Turin, on 1,048 boys and 968 girls⁷ in Lausanne, on 2,000 children;⁸ in Hamburg, on 515 boys;⁹ in Gohlis, on 1,386 boys and 1,420 girls.¹⁰ These references might be indefinitely extended.¹¹

Unless we except the unscientific effort of Lange,¹² whose data include various races for height with little discrimination, and are not worked up according to the scientific methods 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.

From birth to three and one-half, and indeed up to five years, or the beginning of school life, we have measurements on relatively very few children. Toldt and Hecker are still our standards for length, and Schröder and Fehling for weight, during prenatal stages. While there have been many measurements 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 beginning for the pre-adolescent increment and the preceding lowered rate of growth are based on the largest numbers. Combe, Geissler, Uhlitzsch, and Landsberger stopped at thirteen, Carstadt and Hertel at sixteen, Gilbert and Erismann at seventeen, Bowditch and Peckham at eighteen, Pagliani, 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 sometimes contradictory and even anomalous, some even suggesting a shortening of stature or else early mortality among tall people. Baxter’s¹ 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 teachers. Age determinations are often too inaccurate, and frequency of measurements vary. It makes a great difference 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 conditions and so are more likely to die, and where their measurements 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 because 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 overlapping of the curves of boys and girls, for the amount and duration of the latter’s superiority is smaller, the more favorable the conditions of life. Once more, there is a wide difference between 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 concerning 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 symmetrically. 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 sport leading to a new type. Still again, race, climate, poverty 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 different 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’s¹ measurement of the height of each of his four sons from birth to the age of twenty-five years. In the graphic illustration 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 different mother, taller and older than the first, follows a different curve in both height and weight.

Camerer,² 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,³ followed a few boys for seven years.

It is, however, quite remarkable that whethe’r 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 weight a few years later, concerning which much remains yet to be learned; and, fifth, as shown in many but not in all of these studies, a very slight retardation near the period of school entrance with an acceleration shortly after. These are centers of interest for our purpose to be considered in some detail.

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Bowditch¹ 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 supplementary application of Galton’s methods to his data still later, he² 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, régime, 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 between two periods of growth acceleration. The curve of increase at the fourteenth year is steep and for height, continues through four years, reaching its maximum at the fifteenth 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 thirteenth 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 minimum growth is nine. The great acceleration in growth-rate 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 fifteen 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 Hertel, increase in height most rapidly from twelve to fourteen, and boys from thirteen to sixteen; and in weight, girls increase 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 exceptional if not abnormal and can not be called as yet established 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 observation, 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 guineapigs,¹ 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. 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 expression 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 anthropometrists think growth in height to be more or less antagonistic to growth in girth. Hall¹ formulates the following law: When the vertical dimension of the human body is undergoing an acceleration of its rate of growth, the horizontal dimensions undergo a retardation of their rate of growth, and conversely. The two certainly vary independently, 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, relaxation 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, 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 augmented.

Imperfect nutrition checks growth in weight more than it does in height, but whether growth in either of these dimensions 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 variability means that there are two distinct principles or tendencies, 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 greatest 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 becomes 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 thickness later are handicapped in the race of life. Porter well says that the lack of proper relations between height and other physical dimensions is itself ill health. Great height involves increased work for the heart and for the skeletal muscles, and a greater loss of heat, because the surface of the body is larger in tall than in short people of the same weight and bulk. Even on the average, the relation of surface to weight is only about three-eighths in the adult of what it is at birth. The exceptionally tall person, therefore, if not relatively developed in other dimensions, although he may have sufficient income of vitality to meet the demands of life, will fail under strain. Insurance companies discriminate against tall and slender men.

From May, 1882, to February, 1886, Malling-Hansen,¹ director of the deaf-mute institution at Copenhagen, daily weighed 130 of his boys, and for the last two years of that period, daily measured them with well-elaborated precautions to secure uniformity and accuracy. He found that the weight of an average boy from nine to fifteen passed three annual periods of change. The period of greatest growth was from August to the middle of December. During the second four and one-half months till the end of April, growth was of average rate, and it was least for the next three months ending with July. During the maximal period the daily gain was three times as great as in the middle period, while nearly all the gain of the latter was lost in the minimal period. For growth in height, the minimal period begins in August and lasts till near the end of November, the middle period lasts four months till the end of March, and the maximal period lasts four and one-half months to the middle of August. In the middle period the daily increase is twice, and in the maximal, three times as great as in the minimal period. Boys grow thick most slowly while they are growing tall fastest, and vice versa. Increase in weight varies with local temperature, so that all these changes the author ascribes ultimately to the sun.

According to these conclusions, spring growth in height leads with very slight autumnal increment in thickness, and a year or two later, the latter predominates and the former ceases. During the annual as distinct from the longer periodic changes in rate of increase, the season of most rapid growth in height is also the period of least growth in weight, and vice versa. To secure this later thickening of the body to due proportions, so as to prevent the wastes and dangers of tallness and slenderness, is one of the most important desiderata of hygiene and body training. To win back the due proportions between height and thickness and to correct those rarer cases when the converse relation exists, Malling-Hansen suggested that children who are in danger of remaining too short and thick go gradually south to warmer climates toward the end of summer, when the period of maximal growth in weight comes, and so be removed from the influence of the maximal period of growth in thickness. Conversely, a tall, slender child must be removed from the influence of the maximal period of growth in height by being taken slowly north in April. Travel, he suggested, might thus be prescribed to control growth by following spring or autumn, as height or thickness respectively is desired. The practicability of this remains yet to be tested.

Again, adults probably tend to grow thin at the same period when children tend to grow tall, and also to grow thick when children grow heavy. By choosing the former period for cures, fleshy people can aid nature. School vacations should come at the time of the periods of most rapid growth. Even trees grow tall in May and thick in June, resting in one dimension while the other grows. Finally, children eat most in the winter, beginning in December, and reach a maximum in March, when growth in height begins, so that growth does not immediately follow an increase of food-supply.¹

Camerer corroborates Hansen’s facts of seasonal fluctuation, rejecting his cause. Wahl found that Danish children gained in weight during the summer half-year more than during the winter half-year, and that for children below school age there was also a slight difference in the same direction, which was, however, greatly accentuated at puberty. These conclusions do not quite agree with those of Wretkind, the first in this field, who found that girls over nine, in three Swedish schools, grew in weight relatively more in the three vacation months of summer than they did in the other nine months of the year, and this fact he ascribed to the retarding influences of the school. Vierordt² finds weekly or half-weekly periods repeating themselves, so that healthy children are constantly fluctuating.

Many studies show a diminished rate of growth in both height and weight during a few years preceding adolescence. In general, the decrease begins at six or seven and continues with various oscillations until about ten in girls and twelve in boys. Various observers find a period ending at the seventh or eighth year, when the brain has about ceased to grow in weight. Peckham and Vierordt make this age, which about coincides with second dentition, a period by itself. Up to its close, despite the fluctuations, there is relative uniformity of rate, and boys and girls differ but little. West found this age of retarded growth rather uniform, but thought the great diversities that begin with pubescent growth due to heredity and environment. Nearly all the best researches reveal this diminished rate of growth in height and also in weight. Even although the absolute increment is maintained during these minimal years, the percentage rate is usually diminished. The same retardation is also manifest in nearly all returns for weight, although it can not be determined whether height or weight have precedence in this retardation, and this holds for individual as well as mass measurements.

Vierordt thought he discriminated seven growth periods; Liharzik,¹ twenty-four; Zeissing, three; Cohn, two; Key and Lange, four. On Minot’s assumption of senescence as a constantly increasing arrest of growth culminating in degeneration, these rhythms may be conceived as oscillations between two opposing tendencies. This author does not use his hypothesis, however, to account for rhythms, nor is there ground to urge that retarded growth at ten or eleven suggests senescence so much as a diversion of growth energy from other fields. It is a little as if the processes of assimilation made a sudden advance, extending their conquest over non-living substance, and then paused to organize the new acquisition; or else, if it be established that periods of increased food consumption precede growth increments by a considerable period, as if the ashes and cinders of the biological furnace are first removed with exceptional thoroughness to prepare for the extension of life’s combustion to new fuel, so that vitality is first thus raised to a higher level, itself an expensive process, and then the mass it animates is augmented. This is different from the decay of old age, when many cells die from overspecialization, in that it is not compensated and it also is arrest at the bottom rather than at the top of the scale of complexity. Even in the segmentation of the ovum, there is a rhythm of fast and slow and a marked oscillation about the sixth fetal month. Pauses may be to permit adaptation of new-grown cells, tissues, or organs to each other and to the environment. That the amount and time of retardation is exactly compensated during periods of augmentation is a theory that at present lacks confirmation, approximate as this may be for normal individuals. Moreover, there seem to be norms of rates and seasons of growth from which organisms can only with difficulty be much diverted without distinct compensatory tendencies. As in convalescence not only lost flesh but growth is often made up, so hardship, malnutrition, etc., may retard for a time, only to be followed by compensatory acceleration, all the more rapid if the delay has been prolonged up to a certain point, a point probably itself variable. As to whether causes that result in excessive and premature growth tend to react in stationary periods, the evidence is less clear. We also often see what seems to be an illustration of the law laid down by St. Hilaire, that growth in size and in function are inversely to each other, so that when either is progressing rapidly the other tends to be stationary, and the alterations here are often rhythmic, like those between growth in size and in weight.

Will retarded growth be made up or compensated for later? Key thinks that where children grow slowly owing to hard conditions during their earlier years, they will catch up later and end their growth with others who have been more favored. All who have weighed and measured large numbers in such a way that their results bear on this question, indicate, as we have seen, a certain elastic resilient tendency, at least to resume, if not to complete, interrupted or delayed growth, somewhat as the emaciation of disease is compensated. There is reason to believe that weight gained near the normal period for its most rapid increment is more likely to be retained permanently, especially if the muscles are mainly concerned, than if it is won later. We should infer that growth was most advantageous when it was most timely and when the latent energy of tissue-producing power was normal. The opinion which some have held that where one or even several generations have been kept down by hardship, their descendants tend to regain the former height of their race if conditions become favorable, rests on too slight evidence, and indeed seems to have been suggested by the phenomena of alternation of generations.

Concerning the later stages of growth, the data are insufficient and opinions are contradictory. Quetelet, influenced again, no doubt, in part by his mathematical formulae of growth, thought both sexes might continue to grow a little in height till twenty-five, and in weight till perhaps thirty. Liharzik thought growth continued in both sexes till twenty-four or twenty-five, Villerme till twenty-three. Zeissing thinks twenty-one is the time of cessation in growth of both sexes. Venn finds moderate growth in height in male students at Cambridge, England, up to twenty-three, and in weight to twenty-four. Hall finds that boys drop to a very slow rate of increase in height at eighteen, but continue to grow at about that rate for three years; and that in weight, their rate of increase is retarded from eighteen to twenty and then starts up again. The Anthropological Committee concludes that after a retardation at eighteen, boys increase in weight at nineteen or twenty and continue to grow till twenty-three or twenty-four, and that girls pause at nineteen without entirely ceasing to grow, but go on a little more at twenty or twenty-one. Key finds not an entire cessation of growth, but a distinct retardation in weight and height at eighteen or nineteen, with indication of later increment. Roberts asserts an entire cessation of growth in the non-laboring classes of England at nineteen, but thinks in the artisan class, growth is more uniform and extends to the twenty-third year. Smedley¹ found that girls grew in height at a rather uniform but reduced rate from fourteen to seventeen, when they had practically attained their highest stature, and that from just before nineteen until after they were twenty, boys did not grow in height. Beyer thinks that the naval cadets at Annapolis for thirty years show an almost steady increase in weight from fifteen to twenty-three, amounting in all to thirty-seven pounds, and that growth in height shows marked retardation at eighteen; that then comes another increase, closing at twenty-one, and later a third increase, ending perhaps with growth of span of arms at twenty-three. He also infers that tall boys complete their growth earlier than short boys, but that tall and heavy boys are more likely to increase under the influence of gymnastics than those that are small, and that the ratio of increase in height and girth is different in these two classes. Lange thinks there may normally be an infinitesimal growth till senescence, and that it tapers off asymptotically, and one writer conjectures that by this increment, civilized man is slowly growing larger, and that we should so live as to keep on growing till the age of forty-nine, when Plato thought man attained his highest development. Early Amherst reports showed that students, as a rule, do not grow in height from eighteen to nineteen, but that some increase up to twenty-five. Several of the best American colleges report cases of growth of from one-third of an inch to a little over one inch in half a year after eighteen, a result that is ascribed to physical training. Large boys seem not only to achieve their adolescent growth earlier than small ones, but are more likely to keep on growing.

Dr. Edward Hitchcock, who still measures Amherst students and has made many reports, while admitting the meagerness of his numbers for the later years of growth, writes me: I can only say that growth, in our observations, continues up to twenty-six years of age, whether longer or not our data do not show. Beyer, perhaps our most competent authority upon this point, writes me that in a list of height averages based upon 8,000 accepted recruits, it appears that while there is no increase from twenty-four to twenty-five (nearest birthday), there is an increment of one-tenth of an inch at the twenty-sixth year, but that the height then attained is not exceeded by any age up to thirty-five, which is as far as his work has been carried. He says we know that exercise has been followed by a very slight increase in height in some rare instances at a late period in life, and suggests that, if poor personal hygiene or bad conditions prevented men from attaining predestined height during the usual periods of growth, the change to more favorable influences may cause a reawakening of dormant, undeveloped centers and in this manner aid nature in making up for lost opportunities at a later period than is usual.

Dr. D. A. Sargent, of Harvard, whose data published and unpublished are of the highest value, writes; Men usually cease growing in height at about twenty-three, but continue to increase in weight up to fifty. It is a question, however, whether most of the weight accumulated after twenty-five is not more or less abnormal. It may be, however, that this is nature’s way of conserving the body’s heat and storing up excessive carbon to meet the demands of advancing age.

Prof. J. W. Seaver writes me that from his data based on Yale men he can not find an age when there is not a small increment in height or weight, although this is very small after twenty-three years of age. The growth curves of the mass taper off gradually, but those of individuals nearly all show spasmodic growth. As the periods of growth and rest come at irregular intervals in different individuals, I think they tend to neutralize each other in the mass. Persons taking the least exercise grow least, but the opposite is only partially true. The athletes grow more than ‘high stand’ men taking certain severer courses that are confining in their nature. These show slight or no average growth, the slight gain in the few being neutralized by the loss in the others.

From data and opinions so diverse, no inferences of scientific validity can be drawn, and we have little settled knowledge of the laws of growth after eighteen. That there is a general retardation about this age is probable. That there is a later upward tendency in weight in boys can hardly be doubted, and the same is probable to a much less extent in height. Growth seems also to have a far wider range of individual variation as its momentum diminishes near its terminal stages, than earlier in life. It is not unlikely, too, that as a spent ball is more easily stopped or turned, so the later stages of growth are more easily prevented by improper diet or hygienic conditions, excess or defect of exercise, excitement, overpressure in school, vice, or possibly they are transformed into some kinetic equivalent of function, reproductive, motor, or assimilative, etc.

It is hard to realize the complexity of processes involved in the term growth, and yet there is a point beyond which oversubtle methods of weighing and even measuring are mere pedantries. If a child lived in a glass case on the arm of a sensitive balance, and every respiration and all its insensible perspiration, as well as all food and secretions, could be weighed, measured, and chemically analyzed with the utmost accuracy, tentative determinations already made in this direction show that we might be able to estimate to an extent as yet by no means attained, how much loss of each kind was caused by emotional strain or by mental activity, and just when and under what functional and other conditions, growth occurred. But even this interesting physical biography could never tell us what organs were growing large or heavy, or what, if any, small, or which took up and vitalized the ingesta, and in which loss exceeded profit in the chemical bookkeeping of metabolism. The body contains matter in all degrees of organic assimilation, from food just taken and excrement, up to the most controlling parts of the cells in the highest tissues. Cell nuclei or nucleoli, leucocytes, or other invisible and hypothetical chemical components, perhaps brain-cells or the reproductive elements, or whatever else may be thought to be at the high-water mark of organization, and so most vitalized and dynamic, represent a very different level of life and are perhaps as much above simple and lower structures, like bone and connective tissue, as these are above fat, or fat itself above the chip pile of products of decomposition awaiting removal. Individuals differ immeasurably in their nutritive plane; and water and fat, urea and other low-level and waste products may accumulate by reason of imperfect elimination. Growth is really the formation of new cells, the development of cells from granules or, as is more common near the end of the growth period, the further increase in size of cells already well developed. It is these processes that are chiefly sought, and other factors included in growth in weight are not true growth but, in a sense and in varying degrees, errors to be overcome.

Of what actually goes on in the body, then, we know relatively little. No admittance is, as some one has said, the sign which nature hangs out to the physiologist. Could we weigh or measure the gain or loss on any of its higher planes, we might find very different laws of growth. We may conceive our ego as limited by the dermal surface and as scarcely even perforated by the twenty-two foot alimentary canal. We can not say just when the food we take becomes no longer a foreign substance to be acted on, but part of the true physical self, and endowed itself with assimilative power, nor can we say when tissues on the down road of decay cease to be so, any more than the psychologist can tell when the matter of apperception becomes an organ of it. The suggestion is obvious, however, that seasons of rest between growth periods may be times of the greatest qualitative improvement, when what we may call the higher digestion augments the complexity of structure and assimilative processes are carried on upon a higher plane, and all by the same growth impulse as its kinetic equivalent of augmentation in bulk. Of such changes, however extensive or important, determinations of the mass of the body as a whole can give no intimation. Of the laws and processes of growth in individual tissues and organs, our knowledge is but limited, and of those in chemical complexity, we know still less, and yet it is not improbable that these more specific and higher changes are more closely related to psychic development than is growth in height and weight. Mass, cytological change, and chemical complexity and functions, then, are the three factors or dimensions of growth, and many of the mysteries in which it is now shrouded will remain unsolved till we know more of the last two and of their relations. Studies of fatigue and all we know of metabolism indicate that the second factor is far more variable, especially within short periods, than mass, as well as far more closely associated with function.

The rate of growth is a result of many determinants. Race and heredity seem to decree for every individual being an approximate ultimate size, and the way in which total growth is distributed over the years in which it occurs, is one of the most characteristic expressions of heredity. This seems to prescribe and ordain almost with an aspect of fatality, as if every person and part strove to attain a certain size decreed by ancestral ids and determinants, which, although due to a less fundamental momentum than that which determines the species, is hard to modify much by training or even environment. In this factor many anthropologists are chiefly interested and many general and special anthropometric inquiries are undertaken in quest of purer and more aboriginal race types. The Patagonians, the North American Indians, especially the Mississippi tribes, and the Scotch are perhaps the tallest, with Swedes, Norwegians, and white Americans as close seconds; while the African dwarfs, Japanese, Eskimos, South Italians, Bushmen, West Africans, Malays, French, and Spaniards are among the shortest races of men. So far as we know not only after, but before puberty these relations are tolerably maintained. Next at least to hair and eyes, stature is thought to be fundamentally determined by race. Women more nearly attain the stature of men among savages than among civilized races, a fact against the theory of progressive equalization of the sexes. Natural as distinct from forced emigrants, Ripley¹ thinks taller than the stay-at-homes. Long-headed or dolichocephalic races are taller than brachycephalic or broad-headed races, and the former seem to have been on the whole represented by the more energetic and civilized peoples, and, some anthropologists add, are characterized by more vigor of limb and energy of action. While city life tends to shorten stature, the city is fed by the tallest youth from the country. Most of the human race are between five feet and five feet ten inches, so that with all the causes of variation, the human species is quite uniform as compared with many animal types. According to Bowditch, American boys are taller and heavier than English boys of the non-laboring classes in public schools and universities, the superiority being somewhat greater in weight than in height. He also found that the greater height and weight of American over Irish children was due more to race than to occupation. Incidentally Peckham found that urban life tends to decrease stature and that intermarriages between Germans and Americans were advantageous because children tend to reach the height of the tallest parent.

While American boys are taller and heavier than others during pubescent years they excel only for a few years, and at nineteen are overtaken and surpassed by Swedish, Danish, and Dutch boys, while Belgian boys and those of northern Italy remain the smallest of those whose growth has been carefully studied. In the same way, Swedish girls excel those of other nationalities, both in height and weight, except during a few pubescent years. Key thinks for both sexes and in both height and weight, growth ceases earlier in Italy and America than elsewhere. Retardation by poverty is most marked in Italy and England, and least so in the United States. Racial influences upon both weight and height seem to assert themselves strongly at puberty.

It has long been held that increase of comfort increases stature and weight. Quetelet was the first to demonstrate this by comparing the measurements of factory children with those of others more favored. Key concludes that in nearly all lands the weak period of development before puberty is lengthened for the poorer children to their cost, and that the prepubescent growth comes later but is more sudden, so that poor and well-to-do children end their growth about the same time. Some infer that boys are more influenced by this than girls, as they seem to be by many other of the factors of environment. Bowditch concluded that the superior size of children of American parentage in the Boston schools is partly due to the greater comfort and partly to race, but thinks the former more potent than the latter. In England, Roberts found that in the better classes, prepubescent growth began a year or two earlier than among laborers, and that the former were more variable in height and at least two inches taller. The anthropometric committee’s study in England found that boys from the better classes at ten were 3.31 inches taller and 10.64 pounds heavier than industrial schoolboys, and at fourteen they were 6.65 inches taller and 21.85 pounds heavier. In Leipzig, children paying eighteen marks