TECHNICAL PART
In a book the technical part can serve only to point the way, because
the acquirement of technique demands _practical experience_.
The technique of anthropology consists, essentially, of two principal
branches: 1. the gathering of anthropological data by means of
measurements (anthropometry) and by inspection (anthroposcopy); 2. the
formulation of laws based on these anthropological data.
Anthropometry requires a knowledge: a. of anthropometric instruments;
b. of the anatomical points of contact to which the instruments must be
applied.
For beginners it will be found helpful to mark upon the subject the
anthropometric points of contact by means of a dermographic pencil.
In anthropology so large a number of measurements are taken, both from
life and from skeletons, that a minute description of them all would
demand a separate treatise. We shall limit ourselves to indicating such
measurements as it has been found of _practical_ _utility_ to take in
school.
THE FORM
In the theoretic part of this work we emphasized the word _form_,
representing the body as a whole and embodying the conception of
relationship between the proportions of the body, tending to determine
the morphological individuality.
From the normal point of view the two individualities which are most
interesting and worthy of comparison are those of the _new-born
child_ and the _adult_ (see Fig. 140 and its eloquent testimony). In
these two individualities the greatest possible prominence is given
to those differences of proportion between bust and limb on which
all the various measurements of the form depend: the _standing and
sitting stature_; _the total spread of the arms_; the _weight_; the
_circumference of the thorax_ (see "Theoretic Lessons on the Form").
With the theory recalled to mind we may now pass on to the _practical
procedure for obtaining these various_ _measures_. Among them the most
important is the _stature_, whose cycle is represented in Fig. 141. The
theoretic section of this book devotes special attention to the stature
in a separate chapter following that on the Form. It is well to have
in mind the general principals before taking up the technique of the
separate measurements.
_Stature._--The stature is the distance intervening between the plane
on which the individual stands in an erect position and the top of his
head.
[Illustration: FIG. 140.--_New-born child_ and _adult man_ reduced to
the same height and preserving their relative bodily proportions. The
head of the new-born child is twice the height of that of the adult and
extends downward to the level of the latters's nipples. The pubes of
the adult correspond to the navel of the new-born child; and the pubes
of the child to the middle of the adult's thigh.]
_Technical Procedure._--It is necessary to know how to place the
subject in an erect position, heels together and toes turned out,
shoulders square, arms pendent, head orientated, _i.e._, occipital
point touching the wall, gaze horizontal.
In measuring the individual stature it is customary to use an
instrument called an anthropometer (Fig. 142).
It consists of a horizontal board on which the subject stands, a
stationary vertical rod marked with the metric scale against which the
subject rests his back, and another small movable rod perpendicular to
the first and projecting forward from it; this is lowered until it is
tangent to the apex of the cranium; and the scale upon the upright rod
gives the number corresponding to the stature.
[Illustration: FIG. 141.--Diagram representing the cycle of stature of
man (unbroken line) and woman (dotted line), from birth to the end of
life.]
Certain anthropologists are now trying to perfect the anthropometer
(Mosso's school). And, indeed, how is it possible to bring the
entire person posteriorly in contact with the vertical rod of the
anthropometer? The rod is straight while the body follows the curves
of the vertebral column and the gluteus muscles. Accordingly,
Professor Monti, an assistant to Professor Mosso, has proposed a new
anthropometer which, in place of the single rod at the back, has a pair
of rods, so that the more prominent portions of the body may occupy
the intermediate space; a similar anthropometer was already in use for
measuring kyphotics.
[Illustration: FIG. 142.--Anthropometer.]
[Illustration: FIG. 143.--A square.]
At the present day there are exceedingly complicated and accurate
anthropometers which comprise, in addition, instruments for obtaining
various other measurements, such as the thoracic and cephalic
perimeters, etc. But these are very costly and not practical for use
in schools. Their use is confined chiefly to medical clinics, as,
for example, Viola's anthropometer, which is used in Professor De
Giovanni's clinic.
Broca recommends to travelers an anthropometer consisting of a
graduated rod with a movable index attached. By means of this a series
of distances from the ground can be measured, and consequently various
partial heights of the body, from the ground to the top of the head,
from the ground to the chin, to the pubis, to the knee, etc., but grave
errors may be committed and its use is not advisable so long as we have
within reach a universal anthropometer.
The universal anthropometer consists essentially of two planes
perpendicular to each other; now we may say that in every room,
in the meeting of two planes, the floor and the wall, we have an
anthropometer. There is no reason why we should not make use of this
simple means! Placing the child in an erect position with the body
touching the wall throughout its whole length, we place a perfectly
horizontal rod tangent to the top of the head, we make a mark upon the
wall, and then with a millimetric measure we take the distance between
the mark and the floor, and this gives us the stature. Two difficulties
are met with, first, that of holding the rod horizontally on the top of
the head, and secondly, that of measuring the distance in a perfectly
vertical line. In the first difficulty a carpenter's square may help us
or, if there is a school of manual training within convenient reach it
is easy to have a little instrument constructed (Fig. 143) consisting
of two planes perpendicular to each other, one of which should be
held tangent to the head while the other is pressed against the wall
(carpenter's square).
As regards the vertical measurement, a plumb line may be used, but
it is more practical to trace upon the wall that we mean to use for
such measurements, a design consisting of a vertical line on which a
mark may be made at the height of one metre from the floor in order to
simplify the task of measuring.
It is better if the millimetric tape is made of metal, so that it will
not vary in length; but even a tailor's measure of waxed tape may
answer the purpose if it is new and has been tested with a metallic
measure or an accurate metre rule.
The height of the stature is taken _without the shoes_, and it is
necessary to state at what hour of the day the measurement is made,
because in the morning we are taller (though by only a few millimetres)
than we are in the evening. The stature may also be taken in a
recumbent position (length of body), and in this case will be longer by
about one centimetre.
Consequently in giving the measure of stature it is necessary to state
in what position the subject was placed, by what method the measurement
was taken (whether with an anthropometer or not) and at what hour of
the day the measurement was made.
It is not necessary to say that the subject was required to remove his
shoes, since that is taken for granted.
_Sitting Stature._--Besides the stature taken on foot, the sitting
stature (height of bust) is also taken by an analogous process. It
is the distance between the plane on which the individual is seated
and the vertex of his head. The subject should be seated upon a wooden
bench having a horizontal plane and should place his back in contact
with the wall; just as in the case of the preceding measure the shoes
had to be removed, in the present case the clothing is discarded,
leaving only the light underwear (Fig. 144). With the aid of the square
we find the point corresponding to the vertex of the head and with the
millimetric measure we obtain the distance on the wall between this
point and the plane of the bench.
[Illustration: FIG. 144--(1) Sitting stature. (2) Standing stature.
(Method of taking measurements with the Anthropometer.)]
_Index of Stature._--We know that these two measures are extremely
important for ascertaining the type of stature, _i.e._, _macroscelia_
and _brachyscelia_, determined by the proportion between the sitting
stature and the total stature reduced to a scale of 100, that is, the
relation of the bust to the total height of the individual. Let us
remember in this connection that the bust should be a 52d or 53d part
of the total stature and that below 52 down to 50, it is macroscelous,
and that above 53, up to 55, it is brachyscelous.
Having obtained the two numbers corresponding to the two statures,
_e.g._, stature 1.60 m., bust 0.85 m., how are we to find out the
percentual relation between the two measurements? First, we form an
equation: 85:160 = _x_:100.
from which we obtain _x_ = (100x85)/160 = 53
This stature is of the normal average type, that is, it is
mesatiscelous; but the mesatiscelia is high (in comparison with the
other measurement that is also mesatiscelous, namely, 52), in other
words, it is _brachy-mesatiscelous_.
Note the formula which gives us the value of _x_. If we substitute
general symbols in place of the concrete values, we may say that _x_
is equal to one hundred times the lesser measurement (_m_) divided
by the greater measurement (_M_). If, in place of _x_, we substitute
_I_, signifying index, we may draw up the following general formula of
indices:
_I_ = (100x_m_)/_M_
This formula of relations between measurements is of wide application
in anthropology and is fundamental. Indices of every measurement
are sought for. The one given above is the index of stature, and it
determines the _type_ of stature. All the other indices are calculated
by similar procedure.
[Illustration: FIG. 145.--Method of measuring the total spread of arms.]
_Total Spread of the Arms._--This measurement is taken quite simply.
The subject must place himself with his arms outstretched in a
horizontal direction and on a level with his shoulders. The measurement
corresponds to the distance intervening in a horizontal line from
the tip of one middle finger to the other (FIG. 145). A specially
constructed anthropometer may be used for this measurement. It has
a long horizontal rod adjustable perpendicularly, so that it may be
placed on a level with the shoulders of the subject to be measured.
This rod forms a cross with the other vertical rod with which the
subject should be in contact. The arms are then extended along the
cross rod which is marked with a millimetric scale. But this greatly
complicates the anthropometer, and hardly any anthropometer possesses
this attachment. This measure may be successfully taken with the
very simple aid of the wall. The only difficulty offered is that of
securing a perfectly horizontal position for the arms. For this purpose
horizontal lines, which either happen by chance to be upon the wall or
which may be drawn on purpose, will be of assistance. In order to have
guiding lines suited to different statures, several horizontal lines
may be drawn intersecting the vertical line already traced for guidance
of the millimetric tape measure used in taking the stature.
_Thoracic Perimeter._--The thoracic perimeter is taken on the nude
thorax, in an erect position and with the arms hanging beside the bust,
by applying the millimetric measure in such a way that its upper margin
passes just below the nipples. The tape measure should completely
encircle the thorax in a horizontal plane passing through the mammary
papillae. Since the thorax is in constant motion, we must observe the
oscillations of the tape measure and obtain the average; or else we
may take the measurements during the state of expiration (repose). In
giving the figure it is necessary to specify the procedure followed.
_Vital Index. Index of Life._--Index of life is the name given to the
proportion between the stature and the thoracic perimeter. It ought to
be equal to 50, _i.e._, _Tp_ = _S_/2
_Vi_ = (100x_Tp_)/_S_ = 50 (normal).
_Weight._--The weight of an individual is taken by means of ordinary
_scales_. In order to obtain the weight of the nude person, the
clothing may be weighed separately and their weight subtracted from the
total weight of the clothed person. The weight should be taken before
eating, in order that unassimilated alimentary substances may not alter
the real weight of the subject. If this method cannot be rigorously
followed out, it should be specified how much clothing the subject
retained, whether he had eaten, etc.
_Ponderal Index._--Stature and weight are the most synthetic and
comprehensive measurements of the form. But we need a clear proportion
between these two measures to tell us whether an individual weighs more
or less _relatively_ to his _stature_. It may happen, for instance,
that a stout person of short stature actually weighs less than another
person who is tall and thin; but relatively to his stature he may
on the contrary be heavier, that is, he may have a higher _ponderal
index_. A robust and plump child will weigh in an absolute sense less
than an adult who is extremely thin and emaciated; but relatively
to the mass of his body he weighs more. Now this relative weight or
index of weight (ponderal index) gives us precisely this idea of
_embonpoint_, of the more or less flourishing state of nutrition in
which an individual happens to be. But linear measurements such as the
stature cannot be compared with volumetric measurements, such as the
weight. Hence it is necessary to reduce the volumetric measure--the
weight--to a linear measure, which is done by extracting the cube root
from the number representing the weight. Then the root of the weight
may be compared to the stature reduced to a scale of 100. By forming
a general proportion, in which _W_ represents the weight of a given
individual, and _S_ the corresponding figure of his stature, we obtain:
_S_:[*cube root](_W_)::100:_x_
(where _x_ represents the ponderal index)
hence _Pi_ = (100x[*cube root](_W_))/_S_
The application of this formula would necessitate some rather
complicated calculations, which it would be inconvenient to have to
repeat for a large number of subjects.
But there are tables of calculations already compiled, which are due to
Livi, and which are given, together with other tables, in Livi's own
work, _Anthropometry_ (Hoepli). These are numerical tables, to be read
in the same manner as tables of logarithms. At the top, in a horizontal
direction, the stature is given in centimetres, while in the vertical
column the weight is given in kilograms. The calculation of all the
ponderal indices has been worked out, in relation to every possible
stature and weight. If we look up the ponderal index corresponding to
the figures already cited in illustration (see p. 182), we find that
for the adult the _Pi_ = 23.6, and for the child the _Pi_ = 27.4;
_i.e._, considered relatively the child weighs more in the given case.
This is the true and accurate technical method of finding the relative
proportion between weight and stature.
Accordingly, we have now learned to take all the measurements relative
to the form, to calculate from them the more important indices (or
proportions), such as the index of stature, the index of life, and the
ponderal index. We have also learned to understand and to consult the
tables of anthropological calculations.
THE CRANIUM
_The Head and Cranium._--Let us bear in mind the fact that the word
_head_ is used in speaking of a living person, and _cranium_, of a
skeleton.
The science which makes a study of the cranium is called craniology.
The cranium and the head may be studied either by observing the
external form--_cranioscopy_ or _cephaloscopy_; or else by taking
measurements--_craniometry_ or _cephalometry_. Craniology makes use
equally of cranioscopy and of craniometry: in fact, if cranioscopy
alone were used, certain anomalies might escape attention, because we
can recognise them only by measuring the head; and conversely, if we
confined ourselves to craniometric researches, we might miss certain
anomalies of form, which we become aware of only by attentively
observing the cranium. Frequently craniometry serves to verify
cranioscopy. For example, a cranium may appear to the eye too large
or too small, but certainly if we measure the cranial circumference
with a tape-measure we shall have an accurate decision of a case which
may well be a simple optical illusion. Indeed, we all know how easy
it is to give an erroneous judgment, relying only on our senses; for
the personal equation enters very largely into judgments of this sort.
For instance, a person of low stature easily judges that other men are
tall, and _vice versa_. To the eye of the Italian or the Frenchman,
the hair of young English girls is a pale blond; to the Scandinavians
of the North it is a warm blond. If two men possessed of different
aesthetic tastes and in different frames of mind wish to describe one
and the same garden they will give two widely different descriptions
which will reveal far more of their individual impressions and moods
than of the actual characteristics of the garden described. It is
easy to understand how important it is in scientific descriptions
to exclude completely the influence of the observer's personality.
In the cranioscopic study of a cranium, for instance, the precise
characteristics of that cranium are what must be found and nothing else
whatever, no matter who the student is nor in what part of the world
he is working. But in order to achieve this result it is not enough to
take observations; it is also necessary to know how to observe, and in
observing to follow a scientific method.
_Cranioscopy._--Cranioscopic methods require that the skull shall
be observed from several sides. Blumenbach, who studied crania by
observing them from the vertex, divided them into ovoid, rhomboid,
etc., while Camper, on the other hand, studying them in profile,
classified them as flat, elongated, etc., and the conclusions of the
two scientists were irreconcilable.
[Illustration: FIG. 146.--Facial norm.]
[Illustration: FIG. 147.--Occipital norm.]
[Illustration: FIG. 148.--Lateral norm.]
The cranium must be observed from above, from the front, in profile
and from the occipital part; and in such a manner that the observer's
glance shall fall perpendicularly upon whichever cranial side is under
observation. Hence it is said that the observation is made according
to the norm, _i.e._, according to the perpendicular, and there are
four _norms_ in cranioscopy--_vertical_, _frontal_, _lateral_, and
_occipital_. In this way we may be sure that no anomaly of form will
escape the eye.
There are innumerable anomalies of form. We will indicate only the
principal ones. In order to detect all the anomalies that may occur in
a cranium it is necessary to observe it according to all the norms,
each one of which may reveal a different set of anomalies.
A. _Vertical Norm._--The word _norm_, as we have already said, has here
the signification of perpendicular. To look at a cranium according to
the vertical norm means to let our glance fall perpendicularly upon
the vertex of the cranium. We may do this in one of two ways, either
by raising our head above that of the subject of inspection, in such a
way that our glance falls vertically upon it, or by bending back the
head of the person to be observed until the crown of his head becomes
perpendicular to our gaze. This norm is taken by placing oneself behind
the person to be observed, who, if an adult, should be seated while
the observer remains standing; and by taking the head to be examined
between the two hands in such a way that the extended thumbs and
index-fingers form a horizontal circlet around the cranial walls.
This is the most important of the norms, not only because it reveals
the most important normal forms already described in the text, but also
the greater number of anomalies such as are indicated below.
1. _Crania with Rectilinear Perimeter._--It may happen that the
line bounding the cranial vault is not curved but formed of
broken straight lines from which various geometrical figures
result, producing crania known as trigonocephalic, pentagonoid,
parallelopipedoid, etc.
The most important among these and among all the abnormal forms is
the trigonocephalic cranium, having the base of the triangle toward
the occiput and the vertex toward the forehead. The result of such
formation is that the frontal region is restricted, a circumstance
of obvious gravity. The infantile cranium is normally pentagonoid;
the persistence of this form in the adult is a sign of arrested
development, but not serious. Sergi does not admit this form among
the anomalies when the nodules are but slightly emphasised.
2. _Asymmetrical and Plagiocephalic Crania._--The sagittal plane
divides the cranium into two unequal halves. The asymmetry may be
either frontal, in which case one frontal nodule is more prominent
than the other--anterior plagiocephaly, or else parietal, in
which case one of the parietal nodules is more prominent than the
other--posterior plagiocephaly.
These are the two forms of simple plagiocephaly. It may happen that
there is simultaneously an anterior and posterior asymmetry, and in
such a case it generally happens that if the more prominent frontal
nodule is on the right, the more prominent parietal nodule is on
the left, so that the two more prominent nodules correspond in a
diagonal sense. This is compound plagiocephaly.
Plagiocephaly is extremely common; if very apparent, it constitutes
a grave defect, but not if only slight. For that matter, it would
be difficult to find a cranium rigorously symmetrical, even among
normal persons.
3. _Crania with curved and symmetrical lines_, but in which the
perimeter consists not of a single ellipsoidal curve, but of two
curves.
a. _Clinocephalic Cranium._--The coronal suture has a girdle-like
furrow, in such fashion that there result an anterior and a
posterior curve which together form a sort of figure 8. This
anomaly may be perceived also from the lateral norm.
b. _Cymbocephalic Cranium._--- There is a girdle-like furrow along
the sagittal line, so that the cranium has the appearance of being
divided into two pockets, one on the right hand and the other on
the left.
B. _Lateral Norm._--The observer must stand at the side of the subject
to be observed and look at him perpendicularly to the profile.
We remain standing while we look if the subject is an adult and is
standing up, but we sit down if the subject is a child and is standing;
and we determine the vertical position by moving the subject's head as
the occasion requires.
I note, as seen from this norm, two anomalies in which the
ellipsoidal uniformity outlining the profile of the cranium is
altered.
a. _Oxycephalic Cranium._--The line of the profile is noticeably
raised at the bregma, from which the anterior part of the cranium
continues to rise, almost in the direction of the forehead, instead
of curving backward. In its entirety this anomalous cranium has the
form of a "sugar loaf."
b. _Acrocephalic Cranium._--The line of the profile, on the
contrary, is not raised until near the lambda.
C. _Occipital Norm._--The observer places himself behind the subject
and gazes perpendicularly at the occipital point.
D. _Frontal Norm._--The observer stands in front of the subject and
gazes at him on a level with the forehead.
I may point out only one very important anomaly seen from this norm.
a. _Scaphocephalic Cranium._--The lateral parts of the cranium are
flattened to such a degree that the vault is extremely narrow
along the sagittal line (see Figs. 51 and 52).
_Craniometry._--The _volume_ of the cranium is of high importance
because it bears a relation to that of the brain. In the studies which
have been made relative to the correspondence between physical and
intellectual development, the measurement of the cranial volume comes
first in order.
In measuring the cranium it is necessary to use:
a. _the millimetric tape measure_, b. _the craniometric calipers_, c.
_the compass with sliding branches_, d. _the double square_. In order
to facilitate the task of measuring and to secure uniformity it is
necessary first to locate the craniometric points to which it will
be necessary to apply the instrument. These craniometric points are
easily located on the cranium, where a great number of them have been
studied. In the case of a living person, on the contrary, these points
are reduced to a small number because of the difficulty of accurately
locating them.
The points on the vault of the cranium, along the sagittal line, are:
1. The _nasion_ (point of union of the nasal and frontal bones).
2. The _ophryon_ (middle point of the line tangent to the two
superciliary arches, a line corresponding to the horizontal drawn
transversely across the forehead and passing through the two points on
the temporal lines which are nearest to the median line. This point
lies in an important region of the forehead, situated between the two
eyebrows--the glabella. The central point of the middle region of the
forehead above the glabella is called the _metopion_).
3. The _bregma_ (point of juncture between the coronal and sagittal
suture).
4. The _vertex_.
5. The _lambda_ (point of juncture between the sagittal suture and the
occipital or lambdoid suture).
6. The _occipital point_.
7. The _inion_ (situated at a level midway between the occipital point
and the occipital foramen).
Laterally we have these other craniometric points:
1. The _external orbital apophysis_ (formed from the frontal bone).
2. The _supra-auricular_ point.
3. The _auricular point_ (corresponding to a little depression which
may be felt just below the tragus and in correspondence with the
zygomatic arches).
4. The minimum _frontal point_ (a bony angle which may be felt about
1 centimetre above the external orbital apophysis, along the temporal
line).
On a living person the following points can easily be located:
Along the sagittal line:
1. The _nasion_.
2. The _ophryon_.
3. The _vertex_.
4. The _occipital point_.
Laterally:
1. The _external orbital apophysis_.
2. The _supra-auricular point_.
3. The _auricular point_.
4. The _minimum frontal point_.
Now, with these points as guides it becomes practical to measure the
various curves and diameters of the cranium. The curves are measured by
means of the millimetric tape; the diameters by means of the calipers.
There are various curves; we shall confine ourselves to considering
only the following:
The _maximum circumference_, which is obtained by passing the tape
across the ophryon, the occipital points and the supra-auricular
points, beginning to apply it at the ophryon. Its measure varies from
520 to 540 mm. in man and from 490 to 510 mm. in woman, if taken from
the skull. In the case of a living person 20 mm. should be added.
If we find a circumference greater than normal, we are beginning to
enter upon the anomaly which goes by the name of _macrocephaly_. If, on
the other hand, the maximum circumference is notably smaller, we are
entering upon the anomaly of _microcephaly_.
_Measurement of Diameters.--Maximum Antero-posterior Diameter._--With
the left hand place one branch of the calipers upon the glabella; the
other extreme point is to be sought tentatively along a vertical line
dividing the occiput in two halves. Partially close the calipers by
means of the screw and then make trial by raising and lowering the
posterior branch. It ought to move with a slight friction.
This is the classic diameter which measures the maximum length of the
cranium and which, as we have seen, it is customary to compare with
the width in order to obtain the cephalic index. In the adult man it
normally oscillates between 170 and 180 mm.
[Illustration: FIG. 149.--Inspecting cranium (lateral and vertical
norms).]
_Maximum Transverse Diameter._--This measures the width of the
cranium. The investigator places himself in front of the subject in
order to keep the compass quite horizontal through the guidance of
the eyes. The maximum distance is found by experimenting. It normally
corresponds very nearly to the supra-auricular points. In children
this diameter is frequently situated higher up toward the parietal
nodules; in men of tall stature, in whom the cranial vault is generally
slightly developed, this diameter may be found, on the contrary, lower
down, near the mastoid apophyses. If this diameter occurs similarly
low down in children, a notable growth in stature may be prophesied
(Manouvrier); and if inquiry is made it will be found that the parents
are very tall. This diameter measures, in the adult, from 140 to 150 mm.
_Vertical Diameter._--This measures the height of the cranium from
the occipital foramen to the bregma. This diameter cannot be measured
directly excepting on a skull; in the case of a living person its
projection is taken, which, though far from accurate, is given by the
distance between the vertex and the external auditory meatus.
It is necessary to use the double square. The horizontal branch is
placed tangent to the vertex, its direction should be perceptibly
parallel to the transverse orbital line, the graduated vertical branch
should pass over the auricular foramen. The required number may be
read, corresponding to the point of the tragus.
The height of the cranium is exceedingly important; its variations
produce variations in the physiognomy.
In the first period of childhood, the cranium is very low in comparison
to its width; this is also true of dwarfs. In these cases the width of
the cranial vault is large in comparison to that of the base; a low
cranium bulging above is distinctive of babies and dwarfs.
In the adult this diameter measures from 130 to 140 mm.
Among the other measurements which an taken on the cranium, the
following may be cited:
The _antero-posterior metopic diameter_: from the metopic to
the occipital point. In children it is sometimes the maximum
longitudinal diameter.
The _ophryo-iniac diameter_ from the ophryon to the inion.
The _minimum frontal diameter_: between the two minimum frontal
points.
The _maximum frontal diameter_: between the two external orbital
apophyses.
The _bistephanic diameter_: between the two stephanic points.
The _bitemporal diameter_: this is the greatest width of the
cranium between the verticals passing through the base of the
tragus.
The _biauricular diameter_: the craniometrical points are in front
of, and a little below, but very near to the upper insertion of the
auricle. They are little depressions that can be felt, as we have
already said, by applying the finger along the upper edge of the
root of the zygomatic arch.
_Height of forehead_: from the ophryon to the roots of the hair.
Circumferences and Curves:
_Anterior Semicircle._--The tape is applied from one
supra-auricular point to the other, passing through the ophryon;
it corresponds to the anterior part of the maximum circumference.
Manouvrier measures it in correspondence to the verticals erected
from the tragus.
_Posterior Semicircle._--This is obtained by subtracting the
anterior semicircle from the whole circumference.
_Vertical Curve of the Head._--The tape passes through a plane
that is vertical to the orientated head, starting from the
supra-auricular points or from the tragus, according to different
authorities.
_Cephalic Index._--This is the proportion between the _maximum_
_transverse_ and _longitudinal_ diameters. It is obtained by applying
the familiar formula:
_Ci_ = (100x_d_)/(_D_)
in which _d_ represents the transverse diameter and _D_ the
longitudinal. The index represents the percentual relation between the
two diameters, and is obtained from the formula by reducing the greater
diameter to a scale of 100, as follows:
_D_:100 = _d_:_X_, _whence_ _X_ = 100x_d_/_D_
Instead of working out the calculations, we may find the required index
in the tables already compiled.
_Volume._--The volume of the cranium cannot be taken directly, except
in the case of a skull. After the various osseous foramina have been
closed, the cranial cavity is filled through the occipital foramen with
any one of a number of substances (millet, shot, water, etc.), which is
afterward measured. The method of taking this measurement is practised
on a facsimile of a cranium already calculated, and usually made of
metal.
But in the case of a living person the direct calculation of the
volume is impossible. Nevertheless various empirical methods have
been sought for obtaining this measurement, even though imperfect and
approximate. Recently renewed use has been made, especially in France,
of an approximate calculation made by means of Broca's cubic index.
The volume of the cranium is equal to half the product of the three
diameters, divided by an index which varies according to age.
This index is as follows:
/ men 1.20
Adults from 25 years upward. \ women 1.15
/ men 1.15
Young persons from 25 to 20 years. \ women 1.10
/ men 1.10
Young persons from 20 to 16 years. \ women 1.08
/ 15-10 years 1.07
Children of both sexes. { 10-5 years 1.06
\5 years and below 1.05
An index of cranial development is afforded by the maximum
circumference. The average volume of the normal adult cranium is about
1,500 cubic centimetres: _mesocephalic cranium_.
When the cranium is much inferior in volume, it is called
_microcephalic_ (from 1,200 down to 700 cubic centimetres). When
on the contrary it is much superior (from 1,900 up to 2,200 cubic
centimetres), it is called _macrocephalic_ or _megalocephalic_.
For the face, the following craniometric points should be noted:
Along a longitudinal line:
1. The _nasion_ (point of meeting of the nasal and frontal bones).
2. Subnasal point (meeting of nasal septum with upper maxilla).
3. _Upper alveolar point_ (between the two upper incisors at their
point of insertion).
4. _Lower alveolar point_ (point corresponding to the above, in the
lower maxilla).
5. _Mental point_ (middle point of the chin).
The following craniometric points are situated laterally.
6. _Auricular point_ (corresponding to the auricular foramen; in living
persons it is situated on the tragus).
7. _Malar point_ (on the malar bones).
8. _Zygomatic point_ (corresponding to the zygomatic arches).
9. Gonion or goniac point (angle of mandible).
The face also may be studied by inspection--_prosoposcopy_; and by
measurement--_prosopometry_.
_Prosoposcopy._--We proceed to inspection according to two norms: A.
facial norm; B. lateral norm or norm of profile.
A. _Facial Norm._--If it is a question of a living person, we make
complete inspection of the visage, from the roots of the hair to the
chin. First of all we direct attention to the forehead, which will
give us an index of the development of the anterior region of the
brain; next, we observe whether a plane passing longitudinally through
the median line would divide the face into two equal halves (facial
symmetry).
From an aesthetic point of view, the three following vertical distances
ought to correspond in length:
_Height of forehead_ (from the roots of the hair to the nasion).
_Length of nose_ (from the nasion to the subnasal point).
_Labio-mental height_ (from the subnasal point to the point of the
chin). And in regard to width the three following horizontal distances
ought, according to the aesthetic laws of art, _very nearly_ to
correspond (especially in the female face):
_Width of forehead_, between the two external orbital points.
_Bimalar width_, between the two malar points.
_Bigoniac width_, between the two gonia.
It should be remembered that the standards of _beauty_ do not
necessarily coincide with those of _normality_.
B. _Lateral Norm._--In observing the face according to this norm, three
facts should be chiefly noted:
1. The relative volumetric development between facial and cerebral
cranium.
2. The direction of the forehead, which, in the normal profile, ought
to be vertical.
3. Whether the facial profile protrudes or not beyond the extreme
anterior limit of the forehead.
_Prosopometry._---Many forms of measurements are taken on the skeleton
of the face and many total and partial indices are obtained, such, for
instance, as the facial index, the orbital index, the nasal index, etc.
Measurements of diameters and angles are also taken on the face of the
living subject and indices are obtained.
We, however, shall limit ourselves to indicating only those
measurements which are taken most frequently in our special field of
application.
The diameters and the height of the face are obtained by the
_craniometric calipers_ and _Mathieu's compass with sliding branches_;
the facial angle is measured in projection by means of the _double_
_square_; and directly, by the _goniometer_.
One mode of measuring the facial angle in projection is that of drawing
the facial profile with the help of special instruments; or else of
taking a photograph in perfect profile and tracing and measuring the
facial angle on the picture.
_Principal Linear Measurements:_
=Total length of visage:= from line of hair root to point of chin.
=Total length of face:= from the nasion to the point of the chin.
_Length of the nose:_ from the nasion to the subnasal point.
_Height of mandible:_ from the upper edge of the lower incisors to the
lower edge of mandible.
_Subnase-mental height:_ from the subnasal point to the point of the
chin.
=Bizygomatic diameter:= between the two bizygomatic arches.
_Bimalar diameter:_ between the two malar points.
=Bigoniac diameter:= between the two gonia.
_Biorbital diameter:_ between the two external borders of the orbits.
_Gonio-mental distance:_ from the goniac point to the point of the chin.
_Auriculo-frontal radius:_ from the tragus or from the auricular point
to the ophryon.
_Auriculo-subnasal radius._
_Auriculo-mental radius._
(The last four measurements, if compared right and left, give an index
of facial _symmetry_; the radii when compared together serve as an
indirect measure of prognathism.)
_Width of nose_ between the external borders of the nostrils (the
branches of Mathieu's compass are placed tangent to the nostrils).
(The index of the nose is obtained from the length and breadth, by
applying the well-known formula of indices; the nose thereupon receives
various names--leptorrhine, mesorrhine, platyrrhine).
_Width of orbit:_ from the inner extremity of the ocular _rima_
(eye-slit) to the external border of the orbit.
_Width of the ocular rima:_ between the two extremities of the _rima_.
_Width of the labial rima:_ between the two extremities of the _rima_.
_Length of the ear:_ from the highest upper edge of the auricle to the
lower extremity of the lobule.
_Index of the ear:_ this is obtained, by the well-known formula, from
the length and breadth. The normal index is 50; the types of ear above
50 are _low_ types.
Anthropologists obtain the facial index from the skeleton, especially
for the purpose of determining the proportion of the face in human
remains found in the geological strata. In such crania the mandible is
wanting, and the teeth are wanting. Consequently, there are several
ways of computing the facial index, because, while the transverse or
bizygomatic diameter, which is considered as the lesser diameter,
always remains constant, the longitudinal, which is considered as the
greater, varies. The longitudinal diameter is calculated sometimes from
the ophryon to the chin, at others from the ophryon to the point of
insertion of the two upper middle incisors. In the first case it is now
less, and again greater than the bizygomatic diameter; in the second
case, it is always less, and the resulting facial index is notably
greater than 100.
The most usual formula for the facial index is the following:
_Fi_ = (bizygomatic diameterx100)/(ophryo-mental diameter)
on the basis of which Pruner Bey gives the following mean averages
according to race, for the general facial index:
Arabs 96.7
Chinese 101.7
Hottentots 105.7
Tasmanians 109.9
Laplanders 124.7
This index is not exact and constant, like that for the cranium;
in fact, in case a person loses his teeth the index is altered.
At the present day, especially in the French school, the anterior
or total facial index is taken into consideration, in which the
vertical diameter is measured from the vertex of the head to the chin
(Collignon), and, consequently, the index is always less than 100. The
following is the nomenclature that results for the anterior facial
index:
Leptoprosopics 62 and below
Mesoprosopics from 62 to 66
Chameprosopics 66 and above
If we take for the measure of _length_ that of the _visage_, _i.e._,
the distance between the middle point of the frontal line of roots of
the hair and the chin, we obtain indices that are higher by 5 than
those of the French school, namely:
Leptoprosopics 67 and below
Mesoprosopics from 67 to 71
Chameprosopics 71 and above
In many cases this index differs in the individual by as much as 10
from the cranial index, as I proved in my work on the population of
Latium. Consequently, anyone who has a cranial index of 81 ought to
have a _visage index_ of 71, etc.
Contrary to what happens in the case of the cranium, the index of
the face varies according to the age, the face being very short in
childhood, and much longer in the adult.
_Angles._--The angles distinguished by anthropologists are so numerous
that it is impossible for us to take them all under consideration.
In the case of a living person, the angles may be measured directly
with the aid of Broca's _goniometer_; the transverse branch passes
across the subnasal point; the two antero-posterior branches are
inserted, with the buttons with which they terminate, into the external
auricular canals; the vertical branch, swinging on a hinge, is adjusted
in such a way that the little rod which it carries at the end rests
upon the ophryon.
This complicated instrument resembles an instrument of torture and
could not be applied to children; furthermore, it is difficult to
adjust, and consequently the angles that it gives are inexact: every
muscular contraction causes the angle to vary. For this reason the
goniometer is impracticable.
If, by means of an instrument we trace the projection of the facial
profile, the facial angle may be taken on such a drawing; it may also
be traced and calculated on a photograph taken in profile.
Broca's angle is that included between the auricular foramen, the
subnasal point and the ophryon.
Camper's angle is that included between the auricular foramen, the
point of insertion of the upper incisors and the metopic point.
We, on the contrary, in _judging_ of the facial angle, or rather of the
existence and degree of prognathism, have resorted to _inspection_,
aided by certain facial lines, namely (Fig. 104):
_a._ _Vertical Facial Line._--If the subject holds his head level,
with the occipital point in contact with a vertical rod, and his gaze
fixed straight before him, then what we call the vertical line is
the line perpendicular to the horizontal direction of the gaze, and
tangent to the extreme anterior limit of the brain. This line, in the
perfect human face, is perpendicular to the horizontal line uniting the
auricular point with the subnasal point, and hence forms a right angle
with it.
_b._ _Line of Facial Profile._--This is the line uniting the nasal
point with the subnasal point. This line is never vertical, and
therefore cannot form a right angle with the auriculo-subnasal line,
but forms an angle that approximates more or less nearly to a right
angle (85 deg.): this is the _facial angle_.
Transversely there is only one line for us to consider, and it has
already been noted:
_c._ The _auriculo-subnasal line_, or _line of orientation_.
_Facial Norm._--Our attention should be directed, as we have already
said:
1. _To the forehead._
This, if anomalous, may be:
Broad (if greater than 133 mm.).
Narrow (if less than 100 mm.).
High (if over 60 mm.).
Low (if under 50 mm.).
2. _To the Symmetry of the Face._--If the face is notably asymmetrical,
in respect to a plane dividing it longitudinally, the fact is at once
perceptible. But a slight asymmetry may fail to be detected either by
measurements (trago-mental diameters) or by inspection. Consequently,
it will be well to follow certain practical rules in making this
observation.
Observe first of all the median line of the face: the bridge of the
nose, the nasal septum, the upper labial furrow and the point of the
chin ought all to lie in the same vertical line; very often a slight
deviation of the nasal septum above the upper labial furrow will
betray the asymmetry; furthermore, the two naso-labial _plicae_ or
folds should be noted, for they ought to be symmetrical in _direction_
and in _depth_; lastly, we must observe the symmetry of the zygomatic
prominences. We shall often discover three concurrent facts: a slight
deviation in the median line of the face usually corresponding to the
nasal septum; a greater depth of one of the naso-labial plicae; and a
greater prominence of the zygoma and the cheek on the same side.
Our attention should next be turned to the correspondence required by
aesthetics between the following three diameters:
Minimum frontal.
Bizygomatic.
Bigoniac.
A very notable difference between these distances may also lead to the
discovery of anomalies.
Sometimes we may discover, even by inspection alone, a notable
narrowness of the frontal diameter, as compared with the other two.
The _bizygomatic_ diameter may show an exaggerated development, and
this is frequently accompanied by a hollowness in the temporal and
upper maxillary regions and by a beak-like prognathism (prominence
of the middle portion of the upper maxilla); at other times this
degenerative sign calls our attention to the mongoloid type.
The _bigoniac_ diameter may also show an exaggerated development due
to the enormous volume of the mandible (criminaloid type--Lombroso's
assassin type). It is necessary to supplement our observation with
the measurement of these three diameters, because it may very often
appear to the eye that the minimum frontal diameter is below the
normal, merely by comparison with the other two diameters which are
overdeveloped; while when measured, it may turn out to be normal. Or,
conversely, the other diameters, the bizygomatic or bigoniac, although
actually normal, may appear overdeveloped, because of the shortness of
the minimum frontal diameter (see "Faces of Inferior Type.")
Meanwhile we must not forget that the following are signs of grave
degeneration:
_a._ The minimum frontal diameter less than 100 mm. (the gravity of
this is increased if at the same time the other two diameters are found
as described in _b_).
_b._ The other two diameters greater than 110 mm. (Lombroso's born
delinquents, assassin type).
_Lateral Norm, or Norm of Profile._--Our attention ought to be
directed, as we have already said:
1. To the direction of the forehead. If abnormal, this may be:
_a._ Receding;
_b._ _Bombe_.
The receding forehead is an indication of an incomplete or defective
development of the frontal lobe of the brain; we find the forehead
notably receding in the microcephalic type.
The _bombe_ forehead is characteristic of hydrocephaly, but may occur
also in the scaphoid cranium. When the forehead is bombe, the facial
angle becomes equal to or greater than a right angle, because the
face recedes beneath the extreme anterior boundary of the brain;
in this case we have the opposite case to prothognathism, namely,
_orthognathism_.
2. Our attention should next be directed to the facial profile, in
order to observe the form and degree of _prognathism_.
The authorities distinguish three principal forms of prognathism:
_a._ _Prognathism_ properly so-called: prominence of the upper maxilla
as a whole.
_b._ _Prophatnia._--Prominence of the alveoli.
_c._ _Progeneism._--Prominence of the mandible--the lower dental arch
projects in front of the upper.
MEASUREMENTS OF THE THORAX
Principal anthropometric points: _acromial_ point; _sternal fossa_;
_xiphoid_ point; _mammillary_ points.
=Measurements.=--_Thoracic Circumference._--Already described among the
measurements of the form.
Recording instruments are now made that are exceedingly complicated and
quite costly, that register the movements of respiration; they are used
in medical clinics, but would be of little practical use in our schools.
_Axillary and Submammary Circumference._--Taken as above, but at
different levels.
_Biacromial Diameter._--This is taken by means of special calipers
called a _thoracimeter_ or _pelvimeter_, because it is used to obtain
the big measurements of the body (thorax and pelvis). The two buttons
at the ends of the branches are applied to the acromial points, while
the measurer occupies a position in front of the subject to be measured.
_Transverse Thoracic Diameter._--The buttons of the thoracimeter are
applied on a level with the mammary papillae, along the axillary lines
(vertical lines descending from the centre of the arm-pits).
_Antero-posterior Thoracic Diameter._--This is also taken at the level
of the nipples: the branches are applied anteriorly on the sternum and
posteriorly on the vertebral channel.
These two diameters serve to furnish the thoracic index:
Ti = (100x_d_ (antero-posterior))/(D (transverse))
_Spirometer._--The subject takes a maximum inspiration and retains his
breath until he has exactly fitted his mouth to the apparatus; then he
emits all his breath in a forced expiration. This causes the index to
rise, and the amount may be read upon it.
_Sternal Length._--From the xiphoid point to the sternal fossa.
_Bimammillary Diameter._--Distance between the two nipples.
=Abdomen.=--It would be really difficult to take measurements of the
abdomen in the school. The principal anthropometric points to remember
are the _umbilical_ point, the two _antero-superior_ _iliac_ points,
the _pubis_.
The distances which it would be useful to take are the following:
_xipho-umbilical_ and _umbilico-pubic_ distances, which give an idea of
the upper development (liver) and lower development (intestines) of the
abdomen, and the _biacromial_ diameter which measures the width of the
pelvis.
[Illustration: FIG. 150.]
_Limbs._--In the case of the limbs also it is by no means easy or
practicable to take many measurements. Consequently it should be
sufficient to indicate that there are a great number of different
measurements for every different segment of the limbs.
There are two principal instruments needed for this: a large compass
with adjustable branches, for the long segments, and a small compass
for the short segments. With the large compass we measure the length of
the upper arm and forearm, the length of the thigh and shin, the length
of the foot. With the small compass we measure the total length of the
hand, its width, the length of the fingers and of the digital segments,
etc.
The circumference of the limbs is taken with the ordinary metallic tape.
In order to fulfil the present-day scope of pedagogic anthropology, it
is sufficient to take only a few measurements (the form and the head),
but it is necessary to take them with great accuracy, and above all,
to _verify_ one's personal ability as a measurer, so that everyone
who wishes to try the experiment may have a reliable method of testing
himself. To this end it is necessary to know how to calculate one's own
special _personal error_.
=THE PERSONAL ERROR=
In anthropometry, a knowledge of the anthropometric points, the
instruments to apply to them, their use and their interpretation, is
not sufficient. There is need of prolonged experience in accordance
with the accepted method and under a practical guide.
As a matter of fact, the degree of accuracy with which a measurement is
taken is always relative, no matter who takes it, but in the case of a
person who has had no practice this relativity may present so wide a
margin as to be practically useless.
To obtain an approximate figure of a measurement means nothing, unless
the figure is supplemented not only by a statement as to which of
the _accepted methods_ was used in taking it, but also by a minute
description of the manner in which this method was carried out.
It is necessary to bear in mind:
1. That the ability to find the anthropometric points implies a certain
knowledge of anatomy; it is a practical research, to be made under the
guidance of a teacher, while the actual finding of the points as well
as the taking of the measurements, should be left to the learner.
2. That the manner of applying the instruments is not without effect
upon the resulting figure: for example, if the compass is held
horizontally in measuring the frontal diameter, the result is different
from what it would be if the instrument were held vertically. If the
compass is held by the extremities of the branches, the diameter is
slightly different from what it would be if the compass was held by the
handle. Accordingly, it is necessary to describe minutely how we are
accustomed to hold the instruments.
3. That the resulting figure differs according to whether or not the
screw has been turned, or whether it has been read _in position_, or by
approaching the instrument to the eye.
4. That when an instrument is old, it registers different results from
those it gave when new; consequently, it is necessary to _verify it_,
before proceeding to take a series of measurements. Hence it is proper
to state not only precisely what instrument is used, but also that the
precaution has been taken to verify it.
But what is still more important is to find out one's own _personal_
_data_.
If the same measurement is taken twice under precisely similar
conditions, the same figure is hardly ever obtained both times;
everyone, even the most experienced, has his own _personal_ _error_. By
practice the amount of this error may be steadily lowered, but cannot
be eliminated. Constant figures are an evidence of dishonesty, of mere
_copying_; they are almost certainly not authentic.
It is important to know one's own _average error_.
It is calculated as follows:
Let us suppose that successive attempts have resulted in the following
figures relative to the same measurement:
9, 10, 11, 12, 8
The mean average of these numbers is
(9+10+11+12+8)/5 = 10
Let us see how the values obtained differ in respect to 10:
9 10 11 12 8
10
-1, 0, +1, +2, -2 = differences from the mean average figure. We now
take the average of these differences, disregarding the plus and minus
signs:
(1+0+1+2+2)/5 = 6/5 = 1.2 = mean average error
The personal mean error is a datum that it is necessary to know in
order to give value to any measurements that we may wish to give forth.
In taking the various test measurements for the purpose of calculating
one's personal error, it is well to use the precaution of not taking
them twice at the same sitting, but after an interval of time, not
only so that all marks will have disappeared that may have been left
upon the skin by the instrument in the act of measuring, but also that
the preceding figure will have faded from our memory. Accordingly, the
measurements should be repeated on successive days and if possible
under the same conditions of _time_ and _place_.
It is well to make a careful choice of the time and place, because
these also have their effect upon the figures.
It will be observed that if the measurements are made in a
well-appointed place, with a steady light, without noises, in short,
without disturbing causes, the personal error is much more easily
decreased, i.e., the measurements are more exact, because the measurer
can better concentrate his attention.
Even the hour of the day has an influence upon the figures. It is
known that none of us has the same ability to perform our various
tasks at all the different hours of the day; for instance, it is not a
matter of indifference whether we ask the pupils in a school to solve
a problem at one hour of the day rather than at another. This is true
of all occupations, and hence also of anthropometry; there are certain
hours of the day at which fewer errors in measurement will be made,
independently of the state of fatigue.
Consequently, it is well to know this individual datum, and to tell at
what hour and in what environment the measures have been taken.
The figures are of more value if they have been compared with the
results of other observers; it is necessary, after we have found our
own average error, to select, for the purpose of verifying our results,
some other observer, of similar experience to our own, and whose
personal error is also known.
Here it is necessary to take into consideration still another
factor--one's personal susceptibility to suggestion. If we have
confidence in the person through whom we verify our figures, we are
inclined to obtain figures equal to his own. We have only to compare
our earlier figures with those since we began to use him as a test,
in order to see _whether_, and _to what extent_ we are influenced by
suggestion. Hence, to obviate this danger it is necessary to obtain our
respective figures without communicating them to each other.
It will also be necessary to take precautions not to be influenced
by suggestion under any other circumstances. For instance, we are in
hopes, while taking a series of measurements of school children, that
we shall be able to prove that the heads of the more intelligent are
larger than those of the less intelligent. In order that the figures
shall be free from alterations due to suggestion, it is necessary that
the measurer, while actually taking the measurements, shall be unaware
which children are better and which are worse, from the intellectual
point of view.
The personal error cannot be calculated in regard to a single
measurement and then applied to all the others, but it must be worked
out anew for every separate measurement; it oscillates variously, as a
matter of fact, in relation to the longer and shorter diameters, the
cranial measurements, and the measurements of the trunk and the limbs.
We are sufficiently skilled to take measurements when we have attained
for measurements of cranial diameters a mean error of from 1 to 2 mm.,
for the vertical cranial diameter one of 4 mm., and for the stature,
one of from 5 to 6 mm.
Finally, in anthropometry, theory is of no value without a long and
intelligent practice, constituting an actual and personal education in
anthropometric technique.
All anthropometric figures have a relative value dependent upon the
extent of this education in the individual investigator.
This is a case in which it may be said that the figures are worthless
without the _signature_.