STUDIES ON PUBERTY. PART I - BMJHAMILTON HOGBEN, J. A. H. WATERHOUSE, and LANCELOT HOGBEN 1. INTRODUCTION Existing literature concerning the onset ofhuman sexual maturity is more extensive

Brit. J. soc. Med. (1948), 2, 29-42

STUDIES ON PUBERTY. PART IBY

HAMILTON HOGBEN, J. A. H. WATERHOUSE, and LANCELOT HOGBEN

1. INTRODUCTIONExisting literature concerning the onset of human

sexual maturity is more extensive with respect tothe female than to the male. This is not surprising,in so far as the menarche is an event more abruptthan any change characteristic of puberty in themale, and one with more far-reaching social conse-quences. Whilst there is no shortage of recordeddata with respect to the menarche, their value is byno means uniform. Many published enquiriesadmittedly refer to statements about its onsetcommunicated by subjects concerned after a moreor less protracted interval, with or without ancillaryconfirmation from other sources (for example, themother). To this category belong, inter alia, suchaccounts as those of Barker and Stone (1936),Bersamin and Gonzales-Bersamin (1940), Boas(1932), Ito (1942), Kark (1943), Kennedy (1933),Michelson (1944), Mills (1941 a and b), Mills andChenoweth (1938), Simmons and Greulich.(1943),Stone and Barker (1937). Other authors either failto state explicitly whether they took any steps toverify the asserted date of occurrence of the event,or are insufficiently explicit about the type ofverification they sought. Among such we maymention Borruat (1941), G6mez (1942), and Pryor(1936). Aside from uncertainties arising from unduereliance on personal testimony in contradistinctionto direct observation, many published accounts areof limited usefulness owing to the nature of thesample selected for the purpose. For instance,some refer to experience of patients at clinics or inhospitals. Among the very few authors who havestudied a more truly representative populationsample and have recorded only the results of directobservation, in contradistinction to assertions madeby the subjects themselves, are Bayer (1940) andEngle and Shelesnyak (1934).Of all the literature we have had access to, none

dealing with the menarche makes available acontinuous picture of concomitant physical changes,such as enlargement of the breasts and proliferationof pubic or axillary hair; but several authors haveattempted to relate onset of menstruation to skeletal

changes of adolescence or to anthropometricmeasurements. Among such are Barker and Stone(1936), Bayer (1940), Boas (1932), Ito (1942),Michelson (1944), Pryor (1936), Simmons andGreulich (1943), and Stone and Barker (1937).More recently Shock (1941-46) has recorded age-changes and sex differences in adolescence withrespect to blood pressure, pulse rate, basal metabolicrate, alveolar carbon dioxide tension, and excretionof sex hormones. Curiously enough, there has beenlittle attention to such metrical indices as moreespecially signalize sexual dimorphism, for exampleshoulder and pelvic width, neck girth, etc. Recentpapers by Borruat (1941) and by Schonfeld (1943) on,pubescence sufficiently emphasize how defective isour knowledge concerning sequence and duration ofthe several manifestations accompanying maturationof the male gonads. Most of the literature dealingwith the male at present available is indeed of verydoubtful scientific value by the very nature of themethods on which it relies. A noteworthy exceptionis a substantial contribution by Ellis (1946). Forneither sex can we turn to accessible informationwhich discloses a panoramic picture of sexualmaturation exhibiting changes of form and functionduring the period between childhood and theattainment of maturity on a chronological timescale. Such a complete survey of the process ofsexual maturation should show the order in whichthe changes take place, the duration of each phase,and the range of normal variability, as well as theinter-relationships of the different phases.

Several authors have discussed variation withrespect to onset of puberty vis-a-vis extrinsic andintrinsic agencies;; but a satisfactory analysis of therelevant variables, genetic, climatic, nutritional, orother, calls for more searching investigation of thesequence of phenomena and the variability to whichthey are subject in a fairly homogeneous populationthan information at present available in the literatureof the subject can supply. There appears to be awidespread belief that considerable differences withregard to the time of onset of puberty separatestocks of different ethnic origin, but available

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30 HAMILTON HOGBEN, J. A. H. WATERHOUSE, AND LANCELOT HOGBENrecords referring to different ethnic stocks domiciledunder comparable climatic conditions do notdisclose spectacular or even significant discrepancies.Authors such as Kennedy (1933), Klineberg (1935),Fluhmann (1936), and others who have reviewed theliterature available concur in recognizing that suchdifferences are dubious, or at best, small. Michel-son (1944) has published data.about the menarchein several sample populations of both whites andnegroes, including in all about 7,000 subjects. Fordifferent samples of whites, the age means extendedover the range 13 - 08 to 13 - 62 years. For differentsamples of negroes, they extended from 13 35 to13 - 99. When we give due weight to the uncertaintyarising from undue reliance on the memory of theindividual subject, we can hardly place greatconfidence in the conclusion that menarche ofnegroes is later than it is in whites. In any case,Michelson found no significant difference betweensuch samples as were comparable with regard tosocio-economic status and age at the time ofquestioning. In view of the highly dubious and atleast trivial nature of differences attributable toethnic origin, as such, we might expect to find agreater unanimity of testimony with regard toeffects of climate. Contrary to the view commonlyexpressed in medical textbooks, writers who havelately reviewed the subject incline to the conclusionthat hot climates delay the menarche.

In this connexion we may mention the writingsof Kennedy (1933), Mills and Chenoweth (1938),Howe (1939), Ito (1942), Mills (1937, 1941 a, b,.1944), Kark (1943), Bersamin and Gonzales-Bersamin (1940), and Kark (1943). These authorsconcur in the definite assertion that menarche occurslater in the tropics than in temperate regions.Whilst their data are open to criticism on groundsstated above, they are at least as reliable as anycited to sustain the earlier and still prevalent beliefthat a warm environment favours early sexualmaturity of the human female. The issue is onewhich clearly invites further enquiry, and it isregrettable that there are no statistically plausibledata with respect to the male subject.

Attempts to probe the role of nature and nurtureby comparisons between the age at menarche ofmothers and daughters and the age at menarche ofsisters, as by Bolk (1923) and by Gould and Gould(1932) are suggestive but inconclusive, if only becausethey rely on personal testimony of an event longafter its occurrence. For the same reason, we maydismiss a copious literature by Mills (1937-44) andothers attesting to a supposedly secular change ofthe date of menarche putatively associated withchange of the social or physical environment. It isnot unlikely that the alleged secular trend signifies

nothing more than a systematic error of memoriza-tion. Authors who have investigated age atmenarche in different social classes incline to theview that girls of the more prosperous sections ofthe community develop earlier. Among those whohave directed attention to this class of variables are:Bersamin and Gonzales-Bersamin (1940), Fluh-mann (1936), Kark (1943), Kennedy (1933), andKlineberg (1935), among other authors.Authors who have made concomitant anthropo-

metric observations have drawn attention to one orother of the following general conclusions:

(i) there is a rapid growth period in the six monthsbefore onset of menstruation;

(ii) the gain in height at this time precedes gain inweight;

(iii) women with later menarche continuc to increasein weight and height more rapidly than earlypubescents;

(iv) women who menstruate later therefore growfor a longer period, become taller and tendto the leptosomate build, while those whomenstruate earlier stop growing earlier andtend to the pycnic build.

There is little basis for comparison between thesequence of some of the most characteristic signpostsof puberty in man and the course of sexual matura-tion in man's nearest allies. The delayed andhighly localized appearance of copious hair otherthan that of the scalp is highly characteristic of manhimself, as the localized alopoecia and coloration-of the buttocks is highly characteristic of thecatarrhines. Yerkes (1943) cites the followingfigures for the approximate age range of pubescence(both sexes):

Gibbon and siamang .. .. 5- 8 yearsOrang utan and chimpanzee .. 8-12Gorilla .. .. .. .. 10-14

These figures suggest no sharp break between theapes and man. Information with respect to thegorilla is fragmentary, but Yerkes asserts that thefemale gorilla does not mature until over sevenyears. Since menarche of the human female mayoccur before nine years of age, we may infer thatthe dates of sexual maturation in the two speciesoverlap appreciably. In Yerkes' laboratory, chim-panzees matured at seven to ten years, earlier thanin records referable to more natural conditions.Zuckerman's observations (1932) on the course ofpubescence with special reference to the sexual skinof the chimpanzee show that it is protracted,lasting about two years. As regards monkeys,Hartman (1931) dates the beginning of menstruation


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of the rhesus macaque at four years.Yerkes gives the same age for the Chacmababoon, but Zuckerman had reported ona male Hamadryas still immature afterfour and a half years' captivity. Dr.Peter Eckstein (private communication)informs us that the onset of menarche inrhesus monkeys of known age in hisexperience is between 21 and 3 years.*

2. SCOPE OF ENQUIRYThe immediate object of the present

enquiry is: (a) to provide a picture of thesequence of changes associated withpuberty in both sexes, with special refer-ence to sexual dimorphism; (b) toexamine variability with reference to boththe onset and the duration of each phasein a relatively homogeneous populationsample. It relies exclusively on directobservations of the subjects by a medicallyqualified investigator in the course ofroutine medical inspection of school- .children. t FIG. I

The ideal method of securing informa- ition of this kind would involve follow-up alof each individual over a period includingthe beginning and the completion of the periodof sexual development; but this procedure wouldnecessitate a very protracted enquiry beset bymany practical difficulties, unless based on smallsamples as in Shock's enquiries cited above.Accordingly, we have adopted an alternative plan,viz. that of recording the level of developmentreached by each child in a sample taken from each ofa sequence of half-yearly age groups starting ateight and a half years. By this means, it is possibleto assess (a) what proportion of individuals in agiven age group have already reached a level definedby the presence or absence of a particular attributeof sexual maturation; (b) for each such age groupthe mean value of any metrical index relevant tomorphogenetic divergence during sexual maturation.The size of the sample examined was 900 girls

and 850 boys,, but the numbers of records whichwere wholly satisfactory were respectively 662 and642. Children of the older age groups attendedone or other of the secondary (grammar) schools inthe Borough of Tottenham; children of the lower

* Since writing the above, the authors have received the EdinburghMedical Journal, vol. 54, June, 1947, containing a useful contributionby R. W. B. Ellis, with the title " Growth in Relation to Maturity."

t We acknowledge our great indebtedness to the EducationCommittee of the Borough of Tottenham, and to its EducationOfficer, to the Principals of the Schools in which examinations tookplace, to Dr. Norah Webster of the Public Health Department of theBorough, for collaboration in examining the children, to Mr. R.Cawley for invaluable assistance in sorting the data, and to MissGladys Haines for preparation of charts.

PUBIC HAR (COdKET0)

_-

10 - -it,-,i -e ,

,00AXILLARY KAIRC0tl)90

,~~~~~~~~~~~~~~~~~~~~~~~s

1.- Representation of cumulative percentages of childrensuccessive age groups with full development of pubic

rnd axillary hair. Boys (black) superimposed on girls.

age group attended primary schools of the boroughunder the same authority. The selected boroughis itself a relatively homogeneous community withrespect to socio-economic level, and the invesvtigatorsused personal knowledge of the local set-up to drawon local primary schools providing instruction forchildren of families at a socio-economic level mostnearly comparable to that of families from whichthe secondary schools themselves recruit theirpersonnel.The ultimate aim of the investigation takes

within its scope an issue of wider interest than statedabove. Design of the records provided for collect-ing: (a) information concerning school progress,health and social habits of the children; (b) anthro-pometric data which may later provide the basisof axiypological prognosis of early or late sexualdevelopment. At this stage, however, our concernis solely with the issue stated above. To that endthe record of every child examined cited its age andsex grading with respect to certain qualitativeattributes as specified below, and measurements toclarify such sexual dimorphism as dates especiallyfrom pubescence. It is a matter of commonobservation that the hips of the adult female arerelatively wider than those of the adult male, andthat the neck of the adult male is relatively thickerthan that of the female before the menopause.We have concentrated our attention on this

31

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9c

so

70

60

so

60

30

2000

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90

so

70

60

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.40

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32 HAMILTON HOGBEN, J. A. H. WATERHOUSE, AND LANCELOT HOGBEN

ti

50%NOT YET STARTED

.50%t,

ta

INCIPIENT COMPLETE

5QO%FIG. 2.-Diagrammatic representation of mean duration of development of characters amenable

to specification by threefold split.

dimorphism, using as background data height,weight, trunk length, and shoulder (bisacromial)width. The qualitative attributes recorded bygrades were as follows:Hair-growth:

(a) pubic absen(b) axillary absen(c) chin absen(d) upper lip absen

Contour ofpubic hair:apica

Breasts:(a) rudimentary(b) nipple retracted

Menstruation:(a) already(b) regular

Testes:

Voice:

retractile

unbroken

aiatitit

shortshortshortshort

intermediate

enlargingnipple normal

not yet

irregular

non-retractile

breaking

copiouscopiouscopiouscopious

Prepuce:removed

Seminal activity:already

Urine:

incomplete complete

not yet

with albumin without albumin

It will suffice to say that reliable records of thepenultimate item proved to be unobtainable and the

horizontal exigencies of school routine limited opportunitiesfor getting a sufficient sample of the last. In

full addition to items mentioned, and to a variety ofother anthropometric data not relevant to thesubject tnatter of this communication, the recordscovered included various qualitative attributes,e.g. eye and hair colour, other than those whichdistinguish the sexes. The main issues with whichwe are here concerned are:

(1) the mean age, and its vanrance at the appear-ance of each of the following characteristics:

broken pubic hair, axillary hair, enlargement of

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STUDIES ON PUBERTY

breasts, retention of the testes in thescrotum, enlargement of the larynx,appearance of hair on chin and upper lip;

(2) the duration of the changes involved in theappearance of the characteristics abovementioned;

(3) delimitation of the date of the menarche;(4) differentiation of pubic hair contour;(5) differentiation of hip width and neck growth.

For the purpose of specifying date of closure of theinguinaL canal, the procedure was as follows: Onfailure of the boy to accomplish voluntary retractioninto the inguinal canal in the prone position, theexaminer ascertained by gentle palpation in turnif either testis could be made to pass through theexternal abdominal ring. It is of minor interest torecord in this context some information withreference to the condition of the prepuce amongthe boys. For the purposes of the ensuing three-fold

split, "removed " signifies that circumcisionhadbeencarried out. Incomplete signifies that the foreskindid not extend to the top of the glans in its normalcondition.

RemovedIncompleteComplete

26-4+1L88-1±1-1

.. 655±1-9

3. COMPUTATION OF AGE DISTRIBUTIONSThe raw data of this enquiry supply us with the

means of plotting graphs which exhibit the incidenceof a given attribute of sexual development inequally-spaced intervals of time. In a graph orhistogram so constructed, age is in effect theindependent variable with respect to which y, thepercentage exhibition of the individual character, isthe dependent one. To assess the course of events,either in terms of median age, or for the purpose ofestimating the duration of the process of sexual

70%

ti

ta

NOT YET STARTED

30%t.

t,

RAA

INCIPIENT

A AAI"L

300l

COMPLETE

&a R R

70c1oFIG. 3.-Diagrammatic representation of mean duration of development of characters amenable to specification by

threefold split.

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34 HAMILTON HOGBEN, J. A. H. WATERHO USE, AND LANCELOT HOGBENdifferentiation, what we need to know is at what a,any given proportion of the population sample battained a specified level of development. In otiwords, the question to which we seek an ans%presupposes that we can express age (y) as t,dependent with respect to percentage incidenceus the independent variable.

Cumulative percentage graphs of the incidencea qualitative characteristic of puberty derived frcthe raw data, as in Fig. 1, are of a sigmoid tyjFor estimation of age in terms of decile incidenlevels, e.g. the age at which exactly 70 per. ceiof girls have attained the menarche, we haemployed two types of sigmoid curve to fit'the dain accordance with' the requirements stated in tpreceding paragraph: (a) a logistic; (b) a protthat is, integral normal.

(a) Logistic curves' are here defined (on a pcentage scale) by' the following equation in whichthe dependent variable, is the age, and x is tpercentage exhibition:

100x= ........................

l+ea -by

The numerical work of fitting curves of this tyto our raw data was carried out by Dr. L. J. Coin

94UINAL CANAL

IIIII

IIII

.. 9 II

d III

I

MENARCHg

095 yr.

IIIS2yyr.115 yr,.

1 9 yrs.

I-a yrs.

4 - 7 yrs.

igeiasherverthe(x)

of)mpe.ce-nt.Lveitathe

and his staff of the Scientific Computing Service.As it stands, the form of (i) is not suitable for leastsquares calculation of a and b. We therefore write:

100 -xea-by=.. =XIeaY

x

(a- by)--loge x'=X

We are thus left with a simple linear regressionequation whose solution involving n, the number ofyearly age groups, is:

n,Xy - !XYy IX+bby.b=- ; a=

n'-ey2 _ (:sy)2 n

)it, Observations involving 100 per cent. or 0 per cent.values are useless for fitting, since they involve

er- indeterminate equations. For the actual computa-y, tions of a and b, the two subsidiary variables, x'he and X, are calculated from x, and tabulated. For

the reasons stated above, n is never greater than 8.To obtain the deciles, for which x= 10, 20....... 90,

(i) again x' and X are tabulated, and the correspondingvalues of y found from the equation.

(b) The computation of an age distribution withrpe regpect to decile development levels by the alterna-xie tive method was carried out for us by the Mathe-

matics Division of the National Phy-sical Laboratory. The assumptioninherent in this method is that wemay regard the sigmoid whichembodies the raw data as the integralof a normal distribution. From theobserved percentage values, x, theprobits or normal deviates, Y,

VOICE corresponding to these percentagesare obtained from probit tables.These values, Y, plotted against thevalues of the independent variable,

AXILLARY HAIR y, should give a straight line if theassumption of normality is correct.Again a regression line is computed,and hence a better approximationobtained. The National Physical

PUBIC HAIR Laboratory used this method ofsuccessive approximation to obtainmaximum likelihood estimates of themean age, standard deviation, and

MAMMARY GLANDS deciles. Besides giving the decilevalues for the ages, we are thus ableto cite the fiducial limits at P=0 95for the mean, standard deviation,-and extreme deciles, as also the-criterion of goodness of fit X2

osis with respect together with the critical value oX2against which it is judged.

10 I 12 13 14 Is 96 17 is

AGE IN YEARS.

FMo. 4.-Duration and median age of metamorphto sexually-differentiated characteristics.

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35STUDIES ON PUBERTYTABLE I

ESTnmATED MEDLAN AGES wrrH SEM -1NTERQUARTILE RANGE (YEARS)

(a) Logistic fit (b) Probit fit

50% infantile at: 50% adult at: 50% infantile at: 50% adult at:(a) Girls

Mammary glands .. 10±0-75 15 8 11*5 ±0-83 16 1±1i45Pubic hair .. .±.11807 13 7 ±-87 12-4±0 83 14-1±I095Axiflary hair .. .. 132±10 14-2±0-92 13-5 ±103 14-8±1 0Menarche .. .. 136 ±0-77 14-3 ±1-25 14 0±0 75 14-8 ±1-05

(b) RoysPubic hair .. .. 12-9+10 150±067 13*6+105 15 3 +0-7SInguinalcanal .. .. 13-5 ±10 13-6±0 95 13-9 ±0 95 14d1±0 95Voice .. .. .. 136±0-97 14 5 ±0 37 14 0±0 83 15-0 0-4Axillaryhair .. .. 148 ±085 160063 152 ±095 164±06Hairofupperlip .. 155 ±10 15 7 ±0 85Hairofchin .. .. 16-±0 75 16-5 ±0 75

We have reason (see section 5 below) to believethat the logistic formula accords more closely withthe trends it describes than does the probit curve,of which the rationale rests on an entirely arbitraryassumption, viz. a normal distribution of theproportion of individuals of a given age grApattaining a given level of maturity. Though thispostulate is attractive from a statistical point ofview, it would be difficult to justify on biologicalgrounds.

4. THE CRIMCAL AGESEach of the attributes specified in Table I admits

a distinction between: (i) the infantile condition;(ii) a transitional stage; (iii) the fully-developed oradult state. In defining a mid-point of a grossprocess on the basis of this split, we may thereforeadopt one or both of two criteria: (a) the time atwhich half the population is still infantile; (b) thetime at which half the population is already adult.For example, we may estimate a time at which:(i) 50 per cent. of our sample have no pubic hairand 50 per cent. have an incipient or copiousgrowth; (ii) 50 per cent. of our sample have acopious pubic hair and 50 per cent. have eithernone or merely a poor growth.We refer to these two critical ages -in Tables I,

IV, and VI respectively as the median age at which50 per cent. are infantile and the median age at which50 per cent. are adult with respect to a specifiedcharacteristic. The corresponding semi-interquar-tile ranges are bounded by the 25 per cent. and 75 percent. levels. Needless to say, direct inspection ofour data does not permit us to specify either the oneor the other. It merely permits us to tabulate theproportions of the three classes in each age group.Such tabulations supply us with the raw data to

which it is possible to fit distributions which permitus to treat the percentage of infantile or the per-centage of adult types as the independent variableand hence to compute an estimated date at which10 per cent., 20 per cent., etc., of the total populationare still infantile or are already adult with respect toa particular characteristic. Table I sets forth thetwo critical ages as above defined in accordancewith two different methods of interpolation.Our data record whether girls examined were

menstruating regularly or not. If we reject indivi-duals who have not yet menstruated or have doneso only once, we may divide those who have attainedthe menarche into two fairly clear-cut categoriesfrom this point of view. Table II shows a threefoldage split of this residual sample. Since the propor-tion of girls with irregular periods diminishes fromthe menarche onwards, we may infer that anappreciable proportion of all girls pass through astage of irregular menstruation before attaining regu-larity; but it would not appear that such a stageinvariably follows the menarche. Consequently ourdata under- this heading do not justify a threefoldsplit en rapport with those referring to otherphenomena of sexual maturity exhibited in Table I.

TABLE IIINCEPTION OF MENSTRUATION

Age group Period Period(years) irregular regular Total


NECK GIRTH (cmQBY AGE

Q0-

FIG. 5.

34,

33.

32

31

30

29

28

27

26.

NECK GIRTH (cmS)BY AGE

0 ALL dd

* 99 MENSTRUATING

QQ NOT YETMENSTRUATING

9Y5 10X 11X 12X ,3X 14j *5a 16kAGE

FIG. 6.

5. DURATION OF PUBESCENCEThe critical ages defined in section 4 provide us

with signposts of the temporal order of the severalphenomena involved in sexual maturation. Wenow have to ask whether our data can supply uswith any information concerning the duration of themanifest processes. It would appear that this ispossible with respect to such attributes as areclassifiable in three grades specified above, viz.(a) not yet started (infantile); (b) incipient (maturing);(c) complete (adult). The analogy of a processionmarching at uniform speed in single file along anavenue with gates at either end suggests a positiveanswer.

Individuals specifiable in this context as not yetstarted are comparable to individuals who have notyet entered the near gate, incipients to those who are

TABLE IIIDURATION OF STAGES (YEARS) BASED ON THE 50 PER CENT.

LEVEL

(a) Logistic fit (b) Probit fit

(a) GirlsMammary

glands . 48 4*6Pubic hair 1*9 1*7Axillary hair 1*0 1*3

(b) BovsPubic hair 2-1 1*7Inguinal

canal* 010I2Voice .. 09 1*0Axillary hair 1*2 1*2

The figures cited here signify the period which elapses betwecnocclusion of one side and occlusion of the other.

TABLE IIIACOMPARISON OF ESTIMATES OF DURATION OF STAGES

(YEARS) BASED ON THE LoGIsTic Frr'

Estimate A Estimate B Estimate C30% level 50% level 70% level

(a) GirlsMammary

glands .. 40 4 *8Pubic hair .. 17 1*9 1 9Axillary hair. . 1*1 1.0 1.0

(b) BoysPubic hair .. 24 2*1 18Inguinal

canal* .. 02 01 01Voice .. 110*9 01Axillaryhair.. 1*3 1*2 1.0

* See remarks in footnote to Table III.

,n

AGE

FIG. 7.

25 ... .,-


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still between the two gates, and the adult class tothose who have passed through the far gate. Ifexactly 50 per cent. of the procession has not yetentered the near gate (Fig. 2) at a time tI = t50, andexactly 50 per cent. have passed the far gate at atime t2 =t5O+ At5O, the difference ( At5o) is the timetaken for an individual to complete the process ofpassing through the avenue. More generally(Fig. 3) we may suppose that exactly x per cent.have not yet entered the near gate at time tI = t,, andthat exactly y per cent. have passed out of the fargate at t2 = ty. The time taken for an individual tocomplete the course between the two gates isty- tx, ify= 100-x. The assumption that speed isuniform is, of course, arbitrary and certainlyinapplicable to our problem; but the above con-siderations suggest that ty- tx is a representativeestimate of the duration of a manifest transformationof the type under consideration. That is to say,the mean interval involved is the difference between:(a) the age at which exactly x per cent. individualsdo not as yet exhibit detectable manifestations ofthe adult trait; (b) exactly (100-x) per cent. arefully mature.The threefold split which our data permit with

respect to the closure of the inguinal canal, that is,both retractile, right or left only retractile, andneither retractile, do not correspond with the threestages specified above as infantile, maturing, and

RELATION OF PHYSIQUE

adult. Accordingly, the time interval specified inTables III and IIIA with respect to the inguinalcanal does not signify the duration of the processof occlusion. What it does signify is the intervalbetween completion of occlusion of the canal onone side and that of occlusion of the inguinal canalon the other side.Table III shows estimates of duration of stages

based on the 50 per cent. level separately in accor-dancewiththe logisticformula and the probit formula.Table IIIA, which refers to the logistic method,shows different estimates respectively consistent withtaking x as 30 per cent. (A), 50 per cent. (B), and70 per cent. (C). The three separate estimatesderived from the probit fit exhibit a systematicerror inasmuch as the B estimate (50 per cent. level)consistently lies between the A and C estimatesfor a given character. On this account we regardthe logistic formula as a more satisfactory descriptivedevice than the alternative specified in paragraph 3above.

6. QUANTITATIVE CRITERIA OF SEXUAL DIMORPHISMIn the course of examining our data with respect

to two outstanding quantitative criteria of sexualdimorphism, namely neck girth and hip width, wecomputed several indices relating the relevantmeasurements to growth along other axes. Forthis purpose we took (inter alia) as our standard of

TABLE IVTO MEDIAN AGE (YEARS)-GIRLS (WITH SEMI-INTERQUARTILE RANGE)

IA: Tall IB: Short IIA: Heavy IIB: Light

(a) Logistic estimate

(i) 50% InfantileMammary glands 11-O±0t75 11.5 ±1 00 11-0 ±0-75 11*0±0-63Pubic hair 11*3 ±0-65 12- 5 ±0-60 12--5 12±1±0-70Axillaryhair 12-6±1-07 13-7±1-00 12-8±0-90 13-3±l-13Menmrche 13 *0±0 75 14-0±0*75 13*4±0*75 135±1I25

(ii) 50% AdultMammary glands .1 15 *7 ±2*00 16-0 ±2 05 14 5 ±i175 (16 8)Pubic hair .. .. 13- 3 ±0-75 14-5±100 13-4±0-68 13-5±1*35Axillary hair .. .. 14-0±105 15-0 ±1-0 0 14.0±085 14-5±1*20Menarche .. .. 13-8±1-35 14-8 ±1-05 14-4±0-90 14-5±1-52

(b) Probit estimate

(i) 50% InfantileMammaryglands .. 11 ±0-75 11-8±0-83 11-0±11 11-8±0-57Pubichair .. .. 1-8±0-8 13-00-65 12-3±0-97 12-5±0-70Axillary hair .. .. 1 ±0* 95 14-1 ±097 13 3 ±0t 95 13*7±1*12Menarche .. .. 136 ±07 14-4 ±0*73 (13*8) 14-1 ±0 87

(ii) 50% Adult.Mammary glands .. 16-3 ±1-6 16-1 ±1-3 15-3 ±1-05 17-4±2-05Pubic hair .. .. 13-5 ±0-9 14-7 ±0-93 13-8 ±0-65 14-4±1-23Axillary hair .. .. 14-5 ±0*97 14-7 ±0*93 14-4±0-8 15*2 ±1*17Menarche 14-4±1*05 15-2±105 14 S±0*95 15S1 +1*2

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38 HAMILTON HOGBEN, J. A. H. WATERHOOUSE, -AND LANCELOT HOOBENTABLE V

RELATION OF PHYSIQuE TO DURATIoN (YEARS) (50 PmCENT. LEVFL)-GIRLS

IA IB IIA IIB(a) Logistic estimate

Mammaryglands . 4-7 4-5 35 (6 0)Pubic hair .. .. 2*0 20 0*9 14Axillary hair .. .. 14 13 1*2 1*2

(b) Probit estimate

Mammary glands .. 52 4 3 4-3 5 *6Pubic hair .. .. 17 1*7 1*5 1*9Axillaryhair .. .. 15 06 1*1 1*5

comparison weight, full height, and trunk length.As regards our immediate objective, these explora-tory computations added little or nothing to thepicture disclosed by the absolute measurementsthemselves; but they served to focus attention on astriking difference with respect to growth along thebisacromial axis. In this context we shall thereforeconfine our attention to direct measurements,deferring for a later communication the analysis of

relative growth in terms of axial gradtents. Thesalient differences are as follows:

(a) Neck girth. Within the age range coveredby the investigation, the mean neck girthof the male (Fig. 5) is greater than that ofthe female of the same age, but the growthcurves diverge noticeably in the four-teenth year, which signalizes a phase ofmore active growth of the male neck.

(b) Pelvic width. Until the thirteenth year,there is no consistent difference (Fig. 8)between the mean pelvic hip width of thegirls and boys of our sample. Thence-forward, in each age group, the absolutemean of the hip width of the female isgreater than that of the male of the sameage. This is because the pubescence ofthe male signalizes the onset of a phaseof slower growth with respect to thetransverse width of the pelvis.

(c) Bisacromial width. At all ages in the rangeof this enquiry, the mean absoluteshoulder width (Fig. 11) of the girl isgreater than that of the male, and thereis no sharp divergence associated with

TABLE VIRELATION OF PHYSIQuE TO MEDiAN AGE (YEARs)-BoYs (WITH SEMI-INTERQUARTILE RANGES)

IA: Tall IB: Short IIA: Heavy IIB: Light

(a) Logistic estimate

(i) 50% InfantilePubichair .. . 12-5+100 l13 4115 12 9±1 20 13-5±1-17Inguinalcanal .. .. 12-9±0 93 14-1+1-00 12-6 ±0*73 14-2±100Voice . .. .. 14-0 135 ±107 14-0 14-0±1 25Axillaryhair 14-5+0 63 15*5±110 14-2±0 78 115*5±0 95Hair ofupperiP .. 15-0 ±0-87 15 - 5±0-87 14-5 ±0-75 16-0 ±0 63Hairofchin .. .. 16-0±0-75 16-5±0-63 15-5±0-75 ; 16-5+0-63

(ii) 50% AdultPubichair .. .* 14-5+063 15-5±0 87 14-0±0 50 15-5±0-75Inguinal canal , 13i 1 ±093 14- 3 ±0-97 12-9 ±0-75 14 3 ±1-05Voice. .. . --Axillaryhair .. .J l55±0 63 16-5 E 15-0±0-63 16-5

(b) Probit estimate

(i) 50% InfantilePubic hairInguinal canal..VoiceAxillary hairHair of upper lipHair of chin

(ii) 50% AdultPubic hairInguinal canalVoice .Axillary hair..

13-2 ±1-013-5 ±0-913-6 ±0-814-7 ±0-6715-3 ±0-7716-2±0 72

14-9±05713 6d0914-8 ±0 3715-9±0-72

14-0±1-114-4±0-9

(14-4)15-9±1-1216-2±0 916'9 ±0-7

15-8±0-814., ±0-8215 3 ±0 3517-0 +0-92

13-1 ±0-9213-3 ±0-8213 6 ±0-7514-6±0-7515-2+0-7216-1±0-27

14-7±-513-5 ±0-814-6±0-3215-8 ±0 7

14-1U1l1514-6±0-9214-4±0 8516-0±1-016-4 +0-8516-9 ±0-65

16 1 ±0 771466±0-915-4±0'2517-1 d0'82


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TABLE VIIRELATION OF PHYSIQUE TO DURATION (YEARs) (50 PER

cENT. LEvEL)-BOYs

IA IB IIA iIIB

(a) Logistic estimatePubichair . 2-0 2-1 1*1 2-0Inguinalcanal .. 0-2 0-2 0-3 0-1Voice .. .Axillaryhair .. .. 1-0 1-0 0-8 1-0

(b) Probit estimate

Pubic hair .. .. 1-7 1-8 1-6 2-0Inguinal canal . 0-1 0-1 0-2 0Voice .. . ..1-2 (0 9) 1-0 1 0Axillary hair .... .. 1 *2 *I 1-1 1 *2 1.*1

puberty. On the contrary, our datasuggest a slight convergence, owing toacceleration of growth among males andretardation among females about thetime of the breaking of the voice of theformer and of the menarche of the latter.

The foregoing assertions merely bring into sharperfocus what is common observation, namely that:(a) enlargement of the neck is characteristic of malesexual development; (b) widening of the pubicregion is characteristic of the female. It might seemthat a purely morphological study could furnish noinformation with respect to the nature of theendocrine mechanisms involved; but we can probefurther if we pay due regard to indications ofendocrine activity supplied by the onset of changeswhich antedate the differential growth of the tworegions under discussion. For instance, we mayseparate the boys of one and the same age group

into those who are respectively infantile and adultwith respect to voice. We are then entitled tosurmise that the mean activity of the interstitialcells of the testis in the latter exceeds that of theformer. Mutatis mutandis, we can make a similarsplit with respect to the output of the relevantovarian hormone or hormones of girls of a givenage group by separating those who have attainedthe menarche from those who have not.Of itself, the mere fact that the growth of an

organ enters on a phase of more active growth atpuberty while its growth pursues its previous coursein the other sex does not prove that such accelerationis the visible sign of the activity of a hormonepeculiar to the sex involved. We might equallyconceive the process as one which would inevitably-occur unless inhibited by a hormone peculiar to thealternate sex. However, it is possible to discrimin-ate between these alternatives by exploiting thedistinction stated in the foregoing paragraph. Thefact that all boys and all girls do not show at exactlythe same age the first visible indications of endocrineactivity associated with their respective -gonadsmakes it possible to associate the activity of one orother gonad with a particular type of differentialgrowth.The accompanying Figures (5-13)* bring this

contrast into perspective. Thus a separation of themale population in successive age groups withrespect to the condition of the voice or to pubichair growth does not divide them into groups ofwhich either conforms much more closely than theother to the female pattern of growth with respect topelvic width (Fig. 10). On the other hand, theseparation of the female population into two groups

* The dotted lines connecting the terminal points in these graphsdraw attention to the fact that the class samples for the correspondingage groups are small, and the points subject to a large error of sampling.

TABLE VIIICoNTouR oF PuBic HAIR

Age Apical Medium Horizontal TotalI % % %,______ _ _ _ _ _ _ _.1

Boys16 34-4±8-4 34-4±8-4 31-2±8-2 100-0

Total .. .. 18-6±33 51-9±4-2 29-5±3-9 100-0

Girls14j 7-8±7-1 45-4± 4-2 46-8± 4-1 100-0Total .. .. 43±1 2 45-7 2-9 50-0± 2-9 100-0

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9 6

9-4

9-2

9.0

8.8

8 6

8.4

8 2

8-0

7.&

7 .

7 4

PELVIC WIDTH (cmS)BY AGE

->- d-0' 9

93 10h lltI 1Z!- 134 14iAGE

FIG. 8.

PELVIC WIDTH (cMs)RV Ar-

9.4

92

9.0

8.8

86

8.4

8 2

80

78

76

IV1 66

(Fig. 9) distinguished by whether they do or do notas yet menstruate isolates a group which conformsto the characteristic female growth pattern from agroup which conforms to the male. Whether thetestis is or is not active does not appear to be thecircumstance relevant to this type of dimorphism.What is decisive is whether the female gonad hascome into action. The same method of analysis(Figs. 6 and 7) throws light on the mechanism ofdifferential growth with respect to neck girth.Before the pubic hair appears the male pursues thegrowth pattern of the female. The acceleratedgrowth with respect to neck girth characteristic ofpuberty in the male is thus attributable to theactivity of the male gonad. As regards bisacromialwidth, our data are less clear-cut. They suggestthat the male and female gonads exercise a contraryinfluence on the course of growth, indicative of theseparate existence of a male growth-promoting anda female growth-retarding hormone.The conclusion that the male hormone is decisive

for neck growth, and that the activity of the femalegonads is decisive for the widening of the hips, doesnot in either case necessarily imply that the hormoneinvolved is sex-specific. We know that castrationof the male of henny-feathered poultry breeds(e.g. Campines) induces the assumption of cock-feathering, as does castration of the female of anybreed. What would at first appear to be a qualita-tive distinction- between the endocrine activities ofthe gonads may thus be merely a difference of degree.On this issue our data offer a suggestive clue. Withrespect to pelvic width, infantile females (Fig. 9)

9 4

9 2

9 0

8 8

86

084

32

8-

7-8

76

7-4

0.0

ALL (S g99 MENSTRUATING99 NOT YET

MENSTRUATING

A

,'

0, 10\ Ilk I2 13 \ 14~ 1Sa 16kAGE

FIG. 9.

PELVIC WIDTH (cms)BY AGE

0 ALL QQ* OC& VOICE BREAKING

OR BROKENo dd VOICE INFANTILE

911.1Z11 1 31 1 1 11-- 9h 108 k 12-', 13 4A ~s 163

AGE

TIG. 10.

appear to be more male than the male.. It would beintemperate to advance either conclusion with anair of finality. We are content to record theopinion that our data lend colour to the possibilitystated above, that is, what we here call the decisiveaction of one or other gonad does not necessarilysignify liberation of a hormone produced by thatgonad alone. On the contrary, our data encouragethe suspicion that the action of one or other gonad

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STUDIES ON PUBERTY

35 BISACROMLAL WIDTH (cMs)34 BY AGE n

33

32

31

30

29

28

27

26

.0- d-a- 9

13

"0. ~~~1 .t 1!2 .h 16

AGE

FIG. 1 1.

is active in a quantitative rather than a qualitativesense.

7. RELATION OF PHYSIQUE TO PUBESCENCEWhilst it is not our intention to attempt an

evaluation of the wider issues involved in therelation between body build and sexual maturation,it is fitting at this stage to record an associationwhich forced itself on our attention at an early stagein the examination of the crude data. The relevantevidence for this association is in Tables IV to VII.For each age group, we have separately calculatedthe indices exhibited in Tables II and III for eachof four classes:

I A and B. The half population with heightbelow the median stature of the samne agegroup; and the half population withheight above it;

II A and B. The half population weighing lessthan the median body weight of the sameage group; and the half populationweighing more.

For each attribute, and for both sexes, the esti-mated critical age with one notable exception (voice)is conspicuously later for the short than for the tall,and consistently, though less conspicuously, laterfor the light than for the heavy half ofthe population.On the other hand, there is no clear indication of anassociation between the duration of pubescence andstature or body weight. Whether this relationbetween stature or body weight on the one hand andthe critical age, already noticed by Ellis (1946), is amanifestation of a genetical difference associatedwith body build or an indication of retardation of

BISACROMIAL WIDTH (cMs)BY AGE

AGE

Fio. 12.

BISACROMIAL WIDTH (CMs)BY AGE

AGEFIG. 13.

sexual growth associated with defective nutrition orpoor health the data presented in these tables do notpermit us to infer. It may indeed be that neitheraltemative offers a correct explanation of thedifference. Acceleration of growth with respect tostature and body weight itself marks the onset ofthe sexual metamorphosis. Hence a sexually moredifferentiated sample of one and the same age groupwill on the whole be taller and heavier than a moreinfantile sample. By extracting from our totalsample the taller and heavier individuals, we are in

Z5 ;m,, -. -..

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42 HAMILTON HOGBEN; J. A. H. WATERHOUSE, AND LANCELOT HOGBEN

fact extracting a sub-sample with a high proportionof individuals at a more advanced stage of sexualdevelopment in each age group. On the other hand,the data of Ellis indicate that boys who reachedsexual maturity at an early date within the frame-work of his investigation had been relatively tallerand heavier several years before its onset. In anycase, we must agree with Ellis that height andweight norms exhibited without regard to the levelof sexual development may be deceptive as standardsfor growth comparisons.

8. CONTOUR OF THE PUBIC HAmIt is a commonplace that the contour of the

anterior margin of the pubic hair is characteristicof the sexes, and the descriptive epithets (apical andhorizontal) employed in section 2 above are self-explanatory. For the entire sample of boys andgirls with some pubic hair, the analysis of our datayielded the following:

Males (%) Females (%)Apical. .. 18-6±3-3 4-3±1-2Intermediate . . 51 9±4-23 45-7±2 9Horizontal .. 295±387 500±2- 9

These figures do not show such a clear-cutdifferentiation as, one might surmise. A threefoldage split shown in Table VIII shows that the hori-zontal contour is more infantile. Up to the endof our age range the proportion of individuals withpubic hair of the type more characteristic of thefully grown male increases in both sexes.

9. SUMMARYFig. 4 sufficiently summarizes the salient features

concerning median ages of development with respectto axillary hair, pubic hair, voice, mammaryglands, and the duration of the process of fulldevelopment vis-a-vis the median age of the men-arche (girls) and the median age of occlusion ofthe inguinal canal (boys). This figure is based onthe mean of estimates obtained by the two methodsof curve-fitting set forth in section 3. Figures 5to 13 exhibit changes with respect to three axes ofgrowth during the course of development, as setforth in section 6, where the possible hormonalsignificance of the differences exhibited is the topicof discussion.

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Documents

STUDIES ON PUBERTY. PART I - BMJHAMILTON HOGBEN, J. A. H. WATERHOUSE, and LANCELOT HOGBEN 1. INTRODUCTION Existing literature concerning the onset ofhuman sexual maturity is more extensive