AFTER having seen that the high estimate of our civilization does not
necessarily imply that the carriers of this civilization have an
anatomical organization superior to that of all other races, we may turn
our attention to a closer investigation of the characteristics of
different divisions of mankind. It is clear that our investigations
cannot be based on vague descriptions of travellers,—who remark upon the
enormous digestive organs of primitive man, or on his small size, or on
the lack of development of his limbs, or even upon his resemblance to
apes,—but on serious studies of anatomical characteristics.
Two problems may be distinguished here which have too often been
confounded in discussions of the mental characteristics of civilized man
and of primitive man. The one relates to the distinctions between races;
the other, to distinctions between the social strata of the same race.
According to the meaning of the terms “civilized” and “primitive,” it is
perfectly conceivable that there may be civilized groups belonging to
different races (like the Chinese and Europeans), and civilized as well
as primitive groups, both belonging to the same race (like the Yukaghir
of Siberia and the Chinese, or like the group of educated negroes in the
United States and the primitive tribes of the coasts of Africa). The
problems presented by the differences between the various races of man,
and by the differences between social groups in the same races, are, of
course, entirely distinct, and each requires separate treatment.
There is one peculiarity common to both problems, which must be
described before we can properly take up their treatment. When we
compare the individuals comprising any one racial or social type, we
find that they are not by any means uniform, but exhibit considerable
variation. When we try to think of a Norwegian and of a negro, two
entirely distinct types will be present to our minds,—the Norwegian,
tall, with blond and somewhat wavy hair, blue eyes, light complexion,
delicate face and nose; the negro, of medium stature, with black and
frizzly hair, dark eyes, dark skin, projecting jaw, and heavy flat nose.
Still, these pictures are only abstractions of what we think we have
noticed most commonly in each type. When we compare the Norwegians among
themselves, or the negroes among themselves, we find that each
individual in each series has his peculiarities, which the others do not
share. There are tall and short Norwegians; their hair is blond or dark,
straight or wavy; their eyes vary from brown to blue; their complexion
is light or dark, their faces more or less delicate. And so with the
negroes. The degree of blackness, the amount of projection of the chin,
the flatness of the nose,—all show very considerable variations.
Experience has demonstrated that in all cases of this kind, one certain
type, one certain combination of features, is most common; and that
deviations in either direction from this type become the rarer, the
greater their amount. Thus the Norwegians show a prevalence of a certain
blond color. Individuals with a color of hair much lighter than the most
common color are the rarer, the greater the difference of their
hair-color from the most common one; and in the same way individuals
with a color of hair much darker than the most common color are the
rarer, the greater the deviation of their color of hair from the common
one. The extent to which such variations occur is not always the same.
In some cases the individuals constituting the group show a remarkable
similarity or uniformity of type; in other cases the diversity of types
occurring in the same community is quite remarkable. We call a series
the more variable, the more frequently deviating types occur in it; so
that the average amount of differences between the individuals
constituting the series and the most common type may be used as a
measure of the variability of the series.
These considerations are of prime importance in all attempts to compare
different races. In some cases differences are found which are
sufficiently fundamental to distinguish easily and definitely one from
another. Thus the color of the skin, color and form of the hair, and
configuration of lips and nose, distinguish the African negro definitely
from the North European. When, however, we compare all the races and
types of man, we find that innumerable transitions exist, which would
make it difficult to state that any one particular feature belongs to
all the individuals of one type, to the exclusion of all others. Thus it
would not be difficult to find among members of the American race, for
instance, lips and nose which approach in form those of the negro. The
same may be said of color. This indefiniteness of distinctions between
different types is due to the variability of the types, which has been
described before, and to the comparatively small differences between the
types.
To give an instance. Negroes have thick lips. Nevertheless the thickness
is not the same among all of them. In some cases it is quite small, in
others very large. Europeans have thin lips, but we can find individuals
whose lips have very considerable thickness. Thus it happens that there
are some negroes whose lips deviate from the normal type in being
unusually thin, and whose lips are therefore similar to those of
Europeans whose lips are unusually thick. The less distinct two types
are, the greater will be the number of individuals in both groups that
are alike. It follows also, from what has been said, that the greater
the variability of each type, the greater will be the probability that
some individuals of the two types compared will be alike. We may perhaps
best express this by saying that the varieties constituting each race
overlap. In many cases, and in some of those that are most important for
our inquiry, this overlapping is extended. Thus I have pointed out the
differences in average brain-weight between different races.
Brain-weights are, however, so variable, that a considerable overlapping
occurs, and that even the average sizes of the brains of the white race
are numerously represented among other races. Medium-sized brains of
whites may be represented by the group of individuals having skull
capacities of from 1450 cc. to 1650 cc. This group embraces 55 per cent
of the Europeans, 58 per cent of the African negroes, and 58 per cent of
the Melanesians. The same result appears when we compare the number of
individuals having great cranial capacities. We find that 50 per cent of
all whites have a capacity of the skull greater than 1550 cc., while 27
per cent of the negroes and 32 per cent of the Melanesians have
capacities above this value. If we were to assume a direct relation
between size of brain and ability,—which, as we have seen before, is not
admissible,—we might, at most, anticipate a lack of men of high genius,
but should not expect any great lack of faculty among the great mass of
negroes living among the whites, and enjoying the advantages of the
leadership of the best men of that race.
On the other hand, we find characteristics in different races so far
apart and so little variable, that an overlapping is entirely or
practically excluded. Examples of these are the frizzly hair of the
negro as compared with the straight hair of the Mongol; the elevation
and narrowness of the nose of the Armenian, and the flatness of the
negro nose; the differences in pigmentation of the North European and of
the Central African.
Investigations on the character of variability, which have been based on
the measurements of the body, on social and economic phenomena, and also
on variable physical phenomena, such as meteorological data, have
resulted in the discovery that almost always the same law nearly covers
the distribution of the numerical values of the observations (Lock,
Bowley).
[Illustration: FIG. 1.]
It has been shown that the values which represent the phenomenon are so
distributed that certain numerical values occur very frequently, and
that the greater the difference between an observation and the value at
which the greatest number of cases are found, the less will be the
number of these observations. The character of this distribution is
shown in Fig. 1, in which the horizontal line represents the numerical
values of the observations, while the vertical distances represent the
frequency of that observation to which the vertical distance belongs. In
the theoretical distribution which is represented in Fig. 1, the
following values of the stature of a number of men are found:—
1415-1455 mm. 5 cases
1455-1495 mm. 11 cases
1495-1535 mm. 44 cases
1535-1575 mm. 135 cases
1575-1615 mm. 325 cases
1615-1655 mm. 607 cases
1655-1695 mm. 882 cases
1695-1735 mm. 1000 cases
1735-1775 mm. 882 cases
1775-1815 mm. 607 cases
1815-1855 mm. 325 cases
1855-1895 mm. 135 cases
1895-1935 mm. 44 cases
1935-1975 mm. 11 cases
1975-2015 mm. 5 cases
When we compare two series of this class which are grouped around
different values, they may overlap each other. For instance, in a people
of tall stature and another one of lower stature, the following
theoretical distribution of numerical values of stature would be
possible:—
I │ II │
1415-1455 mm. │1425-1455 mm. │ 5 cases
1455-1495 mm. │1455-1485 mm. │ 11 cases
1495-1535 mm. │1485-1515 mm. │ 44 cases
1535-1575 mm. │1515-1545 mm. │ 135 cases
1575-1615 mm. │1545-1575 mm. │ 325 cases
│ │
1615-1655 mm. │1575-1605 mm. │ 607 cases
1655-1695 mm. │1605-1635 mm. │ 882 cases
1695-1735 mm. │1635-1665 mm. │ 1000 cases
1735-1775 mm. │1665-1695 mm. │ 882 cases
1775-1815 mm. │1695-1725 mm. │ 607 cases
│ │
1815-1855 mm. │1725-1755 mm. │ 325 cases
1855-1895 mm. │1755-1785 mm. │ 135 cases
1895-1935 mm. │1785-1815 mm. │ 44 cases
1935-1975 mm. │1815-1845 mm. │ 11 cases
1975-2015 mm. │1845-1875 mm. │ 5 cases
[Illustration: FIG. 2.]
In these two series the group of statures from 1575 mm. to 1695 mm.
occurs 1814 times in the first series, 3371 times in the second; that is
to say, 1814 individuals are found in both classes, and 1557 (i.e.,
3371-1814) are found only in the class of people of tall stature. In
Fig. 2 I have represented these two series in one system of coordinates.
Evidently all the individuals who belong to both series, and who are
shown in the surface enclosed between both curves, are found in both
series; and only the others, who are outside of this surface, and who
belong to one of the groups, are not found in the other one.
Bearing in mind these facts relating to types and variability, we are in
a position to turn to a consideration of the characteristics of
primitive man and of civilized man, and of members of distinct races.
We will first direct our attention to the differences between civilized
man and primitive man, both being members of the same race. For the
white race this difference can no longer be observed, because there are
no primitive white men in the strict sense of the term. Nevertheless we
may discover certain analogues. Some of the peasants in the remote
mountain districts of southeastern Europe do not live in a manner so
very different from the way of living of what we ordinarily call
primitive people; for the mode of life of the agricultural Indians of
North America at the time of Columbus, or that of some agricultural
negro tribes, is, so far as nutrition and occupation are concerned,
quite similar to theirs. Also some of the fishermen on the coast of
Europe may well be compared, in their mode of life, with the fishermen
of America or Asia. More direct comparisons may be made among the people
of eastern Asia, where we may contrast the cultured Chinese and the
primitive Amur River tribes, the northern Japanese and the Ainu, the
civilized Malay and the mountain tribes of Sumatra or the Philippines.
Similar comparisons are possible for the negro race when we contrast the
small educated class of negroes in America and the African tribesmen;
and for the American race when we compare the educated Indians,
particularly of Spanish America, and the tribes of the prairies and of
the virgin forests.
It is obvious that in all these cases we are comparing groups of the
same descent, but living in distinct economic, social, and other
environmental conditions. If we find differences among them, they can
only be due, directly or indirectly, to environment. Thus the
fundamental problem presents itself, In how far are human types stable,
in how far variable under the influences of environment?
It is difficult to take up this inquiry on the basis of a direct
comparison between primitive and civilized types belonging to the same
races, partly because material is hard to obtain, partly because the
homogeneity of the race is often open to doubt; but it is at once
apparent that every inquiry into the variability of human types living
under the effect of different types of environment will help us to gain
an insight into the question at issue, so that we are led to a more
general discussion of the problem of the stability or variability of the
form of the human body.
The principles of biological science forbid us to assume a permanent
stability of bodily form. Our whole modern concept of the development of
varieties and of species is based on the assumption of cumulative or
sudden variation. The variations that have been found in the human body
are quite in accordance with this view, and I may quote here a few words
from Wiedersheim’s admirable treatise on the structure of man as an
index of his past history: “In the course of Phylogeny the body of Man
has undergone a series of modifications which still in part find
expression in his ontogeny. There are indications that changes in his
organization are still continuing, and that the Man of the future will
be different from the Man of to-day.” The best illustrations of those
changes are found in the forms of organs which are undergoing reduction.
Thus we may observe that in modern man the little toe is often
two-jointed, a phenomenon presumably due to lack of functional use. This
condition has been observed in races going barefooted as well as in
those wearing shoes, so that it cannot be ascribed to artificial causes.
The teeth also show a tendency to gradual reduction, especially in the
variable size of the molars and of the upper outer incisors. The third
molar, or wisdom tooth, is often retained, and is in most races
considerably reduced in size. Retention or slight development of the
upper outer incisor is also of frequent occurrence. A similar reduction
may be observed at the lower end of the thorax, where the development of
ribs and sternum shows great variations.
The significance of these phenomena lies in the fact that in the
evolutionary series the abnormal occurrences, which are found in
different races in varying frequency, appear as new developments, which,
if they should become normal, would increase the differentiation between
man and the lower forms. The actual proof of increasing frequency of
these features, and of their becoming permanent characteristics, has not
been given, but seems more than plausible.
This inference is strongly supported by the occurrence of rudimentary,
functionless organs, and by the temporary appearance of lower features
during ontogenetic development.
It has been shown that some of these reductions—like the retention of
outer incisors—are hereditary, and thus liable to perpetuate themselves.
To a certain extent this explains the observation that certain
variations occur with greater frequency among primitive tribes than in
civilized man. Most primitive tribes are very small in numbers, or for
long periods, during which they increased in numbers, have had little
intercourse with foreign people. If in such a group any of the original
families showed a certain peculiarity, it must now be found more
frequently than in any other tribes. A case of this kind is the
frequency of supernumerary vertebræ among the Indians of Vancouver
Island, and probably also the frequency of the _torus palatinus_ among
the Lapps. It may be left an open question, whether the frequent
occurrence of the _os Incæ_ among the Pueblo Indians and Peruvians may
be explained by the same consideration. Therefore it may be that the
greater variability of certain races, in regard to these phenomena, is
not an expression of a lower or higher degree of development of the
whole group, as the case may be, but of the presence of a great number
of members of a family which possessed the peculiar character. We do not
deal in these cases with spontaneous variations, but with their
hereditary re-appearance. In other words, if we are to admit the
conclusion that greater variability means a lower or higher stage of
development, it will be necessary first to prove that these variations
appear spontaneously in any member of the group, and do not belong to
certain families in which the feature is hereditary. Otherwise it will
be necessary to prove that in larger groups of mankind the families
exhibiting the particular anomaly had a greater probability of surviving
than others.
However this may be, the occurrence of these variations shows that man
cannot be assumed to have a stable form. It is of course an entirely
open question, how long a time may be required to fix any one of the
variations that we are here discussing.
The general tendency of anthropological inquiry has been to assume the
permanence of the anatomical characteristics of the present races,
beginning with the European races of the early neolithic times.
Kollmann, the most pronounced advocate of this theory, claims that the
oldest remains of man found in the neolithic deposits of Europe
represent types which are still found unchanged among the modern
civilized population of the continent. He has tried to identify all the
varieties found in the neolithic prehistoric population with those
living at the present time.
All studies of the distribution of head-forms and of other
anthropometric traits have shown uniformity over considerable continuous
areas and through long periods; and the natural inference has been that
heredity controls anthropometric forms, and that these are therefore
stable (Deniker).
There is only one exception to this rule. In all cases in which the
anthropometric traits undergo very considerable changes during the
period of growth, the influence of favorable or unfavorable causes makes
itself felt. The investigations conducted by Gould and Baxter during the
war of the Rebellion have shown that the representatives of European
nationalities born in America have statures higher than the
representatives of the same nationalities born in Europe; and it has
been assumed that better nutrition, or perhaps better hygienic and
economic conditions in general, might increase the stature of a people.
These conclusions were confirmed by Bowditch’s measurements of the
school-children of Boston, and by Peckham’s anthropometric work in
Milwaukee. These changes in stature, due to changed conditions, have
recently been demonstrated also in Europe, where Ammon has shown that
the population of Baden has materially increased in size during the last
thirty years. Other corroborative evidence has been obtained from the
study of various social classes, in which Bowditch found an increase of
stature, beginning with the children of unskilled laborers, and
increasing among those of skilled laborers, members of the mercantile
class and of the professional class; and from the observations showing a
correlation between the character of streets occupied by the well-to-do
and the poor, and the stature of their inhabitants (Ripley).
Nevertheless these changes of stature were not interpreted as changes in
type, because they may well be understood to be due to the elimination
of retarding influences, which prevent many individuals from attaining
their normal growth.
The results of the observations on stature are substantiated by other
anthropometrical studies of various occupations. The best-authenticated
fact, because based on the greatest number of observations, is the
difference in type between sailors and soldiers who were measured during
the war of the Rebellion. It was found that sailors had legs as long as
those of the negroes, and correspondingly a shorter trunk, while their
arms were equally as long as those of the soldiers of the army. We may
also call to mind the investigations carried on in the gymnasiums of our
colleges, which show that a series of measurements which depend largely
upon the functions of groups of muscles change very rapidly under the
influence of practice. It will be acknowledged at once that differences
in the use of muscles during childhood, and continued in later life,
must result in differences of structure, either permanent, or at least
temporary.
A study of the conditions of growth shows how such changes in the form
of the body must develop. Setting aside the prenatal development, we
find that at the time of birth some parts of the body are so fully
developed that they are not far removed from their final size, while
others are quite undeveloped. Thus the skull is, comparatively speaking,
large at the time of birth, grows rapidly for a short time, but very
soon approaches its full size, and then continues to grow very slowly.
The limbs, on the other hand, grow rapidly for many years. Other organs
do not begin their rapid development until much later in life. Thus it
happens that retarding or accelerating influences acting upon the body
at different periods of growth may have quite different results. After
the head has nearly completed its growth, retarding influences may still
influence the length of the limbs. The face, which grows rapidly for a
longer period than the cranium, can be influenced later than the latter.
In short, the influence of environment may be the more marked, the less
developed the organ that is subject to it. Data on the unequal rate of
growth of different parts of the body have been furnished by
Weissenberg.
The influence of retardation, so far as it has been studied, seems to be
lasting. In other words, a retardation in development is never
completely made good by long-continued development. When a child,
through unfavorable influences, has grown slowly during a number of
years, it will probably continue to grow longer than other, normal
children; but the total amount of its growth will always remain too
small (Boas and Wissler). On the other hand, children whose development
has been accelerated will reach the adult stage early, but nevertheless
the total amount of their growth will be relatively great. It follows
from this consideration of the effect of retardation and of difference
in period, that not only the absolute size, but also the relative
proportions, of the body, must be influenced by periods of retardation
or acceleration.
The whole trend of the studies of growth thus emphasizes the importance
of the effect of rate of development upon the final form of the body.
Illness in early childhood, malnutrition, lack of fresh air and physical
exercise, are so many retarding causes, which bring it about that the
growing individual of a certain age is in its physiological development
younger than the healthy, well-nourished individual, who has plenty of
fresh air, and who puts his muscular system to good use. Retardation or
acceleration has, however, the effect of modifying the later course of
development; so that the final stage will be the more favorable, the
less the retarding causes.
It seems more than likely, judging from the course of development of a
few simple mental activities that have been made the subject of study,
that mental development follows laws quite analogous to those of
physical development (Meumann).
These facts relating to growth are of fundamental importance for a
correct interpretation of the oft-discussed phenomena of early arrest of
growth. We have seen that among members of the same race a prolonged
period of growth goes hand in hand with unfavorable development, while
an abbreviated period of growth results in larger dimensions of all
physical measurements, and in a superiority of mental activity. In this
statement pathological cases of complete premature arrest of
development, or of over-development, are of course excluded,—cases of
dwarfish growth or of microcephaly, as well as cases of hypertrophic
growth of organs. It follows, that, in judging the physiological value
of arrest of growth, the mere fact that growth ceases in one race at an
earlier time than in another cannot be considered as significant in
itself without observations on the rapidity of growth.
So far, the question still remains open, in how far there may be changes
in the types of man that cannot be explained by acceleration or
retardation of growth.
An attempt has been made by Rieger to explain differences in head-form
as due to the effect of physiological and mechanical conditions, and
Engel emphasizes the effect of pressure of the muscles upon the forms of
the head. Walcher tries to explain different head-forms by the
consideration of the position of the infant in the cradle. He believes
that position on the back produces round heads; position on the side,
long heads. It would seem, however, that the difference of head-form in
large areas of Europe, in which infants are treated in the same manner,
are too great to make this explanation acceptable.
A number of observations have been made, however, which demonstrate
conclusively a difference between urban and rural types. These
observations were first made by Ammon, who showed that the urban
population in Baden differs from the rural population in head-form,
stature, and pigmentation. He accepts the conclusion that we have here
an actual change in type; due, however, not to a direct effect of
environment, but rather to an elimination of certain types in city life:
in other words, an effect of natural selection. This observation is in
accord with observations made by Livi in the cities of Italy, which show
also a difference when compared to the surrounding country. Comparisons
of the normal and hospital populations of London, made by Shrubsall, are
not unfavorable to the assumption of a certain amount of correlation
between morbidity and physical type, although the homogeneity of
material from a metropolis like London, drawn from different social
strata of a large city, remains always open to doubt.
Another explanation, given by Livi, seems to account adequately for the
difference between city and country population, without necessitating
the assumption of any considerable effect of natural selection, which
presupposes an improbable correlation between mortality and fertility on
the one hand, and traits like head-form and pigmentation on the other.
The change of type in cities, so far as it has been observed, is of such
character, that the city always shows greater resemblance to the average
type of the whole large district in which it is located. If the local
rural population is markedly short-headed, the general type over a
larger area from which the city population is drawn more long-headed,
then the city population will be more long-headed, and _vice versâ_.
Unless selection can be demonstrated to occur in a sufficient number of
definite families, this explanation seems simpler and adequate.
Up to quite recent times no evidence of actual changes of type was
available, except the observations by Ammon and those by Livi on the
physical characteristics of rural and urban populations, to which I have
just referred, and some others on the influence of altitude upon
physical form. In the discussions of the distribution of different types
of man in Europe, peculiarities of body-form in certain areas—as in the
mountains of central France, in parts of Tuscany, in the province of
Zealand in Holland, in southwestern Norway—have been explained as due to
the survival of old racial types, to the influence of natural selection,
or to the direct influence of environment, according as the necessities
of the case prompted the investigator to adduce the one cause or the
other, or a combination of any two or of all, as a convenient
explanation of the difficult phenomenon (Ripley). It goes without saying
that haphazard application of unproved though possible theories cannot
serve as proof of the effectiveness of selection or of environment in
modifying types. The effectiveness of selection can be proved only by an
investigation of the surviving members of a type as compared to those
eliminated by death, or of a shifting of population connected with the
selection of a certain type. The influence of environment requires the
direct comparison of parents living under one environment with children
living under another environment.
I cannot give any example in which the influence of selection has been
proved beyond cavil. It seems plausible that in the criminal colonies of
earlier periods, and in the settling of the West by the most vigorous
members of our Eastern population, and in the complementary weeding-out
of strong elements in some parts of New England, this principle may have
been active; but we have no actual data which would connect with
physical types the selection that has undoubtedly taken place.
On the other hand, it has been my good fortune to be able to demonstrate
the existence of a direct influence of environment upon the bodily form
of man by a comparison of immigrants born in Europe and their
descendants born in New York City (Boas). I have investigated four
groups of people,—the South Italians, representing the Mediterranean
type of Europe, which is characterized by short stature, elongated head,
dark complexion and hair; the Central European type, which is
characterized by medium stature, short head, light hair and lighter
complexion; the Northwest European type, which is characterized by tall
stature, elongated head, light complexion, and blond hair. Furthermore,
I have investigated an extended series of East European Hebrews, who
resemble in some respects the Central European group. The traits which I
selected for examination are head-measurements, stature, weight, and
hair-color. Among these, only stature and weight are closely related to
the rate of growth, while head-measurements and hair-color are only
slightly subjected to these influences. Differences in hair-color and
head-development do not belong to the group of measurements of which I
spoke before, which depend in their final values upon the physiological
conditions during the period of growth. From all we know, they are
primarily dependent upon heredity.
The results of our inquiry have led to the unexpected result that the
American-born descendants of these types differ from their parents; and
that these differences develop in early childhood, and persist
throughout life. It is furthermore remarkable that each type changes in
a peculiar way. The head of the American-born Sicilian becomes rounder
than that of the foreign-born. This is due to a loss in length and an
increase in width. The face becomes narrower, the stature and weight
decrease. The head of the American-born Central European loses both in
length and width, more so in width, and thus becomes more elongated. The
face decreases very much in width; stature and weight increase. The
modifications of the American-born descendants of the Scotch type are
not marked, except that stature and weight increase. The American-born
Hebrew has a longer and narrower head than the European-born; the head
is therefore considerably more elongated. His face is narrower; stature
and weight are increased. In none of the types have marked differences
in color of hair between American-born and foreign-born been found.
In order to understand the causes which bring about these alterations of
type, it is necessary to know how long a time must have elapsed since
the immigration of the parents before a noticeable change of type of the
offspring is brought about. This investigation has been carried out
mainly for the cephalic index, which, during the period of growth of the
individual, undergoes only slight modifications. The investigation of
the Hebrews shows very clearly that the cephalic index of the
foreign-born is practically the same, no matter how old the individual
at the time of immigration. This might be expected when the immigrants
are adult or nearly mature; but it is of interest to note that even
children who come here when one year or a few years old develop the
cephalic index characteristic of the foreign-born. This index ranges
around 83. When we compare the value of this index with that of the
index of the American-born, according to the time elapsed since their
immigration, we find a sudden change. The value drops to about 82 for
those born immediately after the immigration of their parents, and drops
to 79 in the second generation; i.e., among the children of
American-born children of immigrants. In other words, the effect of
American environment makes itself felt immediately, and increases slowly
with the increase of time elapsed between the immigration of the parents
and the birth of the child.
The conditions among the Sicilians and Neapolitans are quite similar to
those observed among the Hebrews. The cephalic index of the foreign-born
remains throughout on almost the same level. Those born in America
immediately after the arrival of their parents show an increase of the
cephalic index. In this case, the transition, although rapid, is not
quite so sudden as among the Hebrews, probably because among those born
a year before or after immigration there is some doubt as to the place
of their birth. These uncertainties are due to the habit of the Italians
to migrate back and forth between Italy and America before finally
settling here, and to the indefiniteness of their answers in regard to
the places of birth of the child, which sometimes had to be inferred
from the age of the child and the year of immigration of the mother. As
long as this uncertainty exists, which is hardly present at all in the
data relating to the Hebrews, it does not seem necessary to assume any
other cause for the more gradual change of the cephalic index about the
time of immigration.
The Italian immigration is so recent, that individuals who were born
many years after the arrival of their parents in America are very few in
number, and no individuals of the second generation have been observed.
For this reason it is hardly possible to decide whether the increase of
the cephalic index continues with the length of time elapsed between the
immigration of the parents and the birth of the child.
The explanation of these remarkable phenomena is not easy. Whatever
their causes may be, the change in form cannot be doubted. It might,
however, be claimed that the changes are not due to deep physiological
causes, but to the changes of certain external factors. The composition
of the immigrant population might be such that the people who came here
at different periods had distinct physical characteristics, and that
these are now reflected in the descendants of the older generations when
compared with the more recent immigrants. It can be shown, however, that
the differences between the Hebrews who immigrated at different periods
between 1860 and 1909 are so slight that they cannot account for the
type of the descendants of immigrants. This important point can be
elucidated more definitely by the application of a different method. For
this purpose I have compared the cephalic index of all immigrants of a
certain year with that of their descendants. It appears from these
comparisons that the differences which are exhibited by the whole series
exist also between the immigrants who arrived here in a certain year and
their descendants. This purely statistical explanation of the phenomenon
may therefore be dismissed.
More difficult to investigate is the hypothesis that the mechanical
treatment of infants may have a decided influence upon the form of the
head, and that the changes in cradling and bedding which are made by
some immigrants almost immediately after their arrival in America
account for the changes of head-form. If this were true, the continued
changes among the Hebrews might indicate merely that the American method
of cradling is used the more frequently, the longer the family has
resided in this country. A number of investigators have claimed that the
position of the child on the back tends to produce short-headedness, and
that the position on the side tends to produce long-headedness
(Walcher). There is good evidence that a flattening of the occiput
occurs when a very hard pillow is used and the child lies permanently on
its back. This is the case, for instance, among many Indian tribes, and
similar results might obtain if a swathed child were to lie permanently
on its back. The prevalence of rachitis in New York would favor
distortion due to pressure.
While I cannot disprove the existence of such influences, I think
weighty considerations are against their acceptance. If we assume that
among the Hebrews the children born abroad have a lesser length of head
than those born here because they are swathed and lie more permanently
on their backs than the American-born children, who can move about
freely, we must conclude that there is a certain compensatory decrease
in the other diameters of the head of the American-born. Since this
compensation is distributed in all directions, its amount in any one
direction will be very small (Boas).
The decrease in the width of head that has been observed is so large
that it cannot be considered simply as an effect of compensation; but we
have to make the additional hypothesis that the American-born children
lie so much on their sides that a narrowing of the head is brought about
by mechanical pressure. The same considerations hold good in all the
other types. If, therefore, in one case the greater freedom of position
of the child increases the length of its head, it is difficult to see
why, among the Bohemians, the same causes should decrease both
horizontal diameters of the head, and why, among the Sicilians, the
length should decrease, the width increase.
The development of the width of the face seems to my mind to show most
clearly that it is not the mechanical treatment of the infant that
brings about the changes in question. The cephalic index suffers a very
slight decrease from the second year to adult life. It is therefore
evident that children who arrive in America very young cannot be much
affected by American environment in regard to their cephalic index. On
the other hand, if we consider a measurement that increases appreciably
during the period of growth, we may expect that in children born abroad
but removed to America when young, the total growth may be modified by
American environment. The best material for this study is presented by
the Bohemians, among whom there are relatively many full-grown
American-born individuals. The width of face of Bohemians, when arranged
according to their ages at the time of immigration, shows that there is
a loss among those who came here as young children,—the greater, the
younger they were. Continuing this comparison with the Americans born
one, two, and more years after the arrival of their mothers, the width
of face is seen to decrease still further. It appears, therefore, that
the American environment causes a retardation of the growth of the width
of face at a period when mechanical influences are no longer possible.
I have not carried through the analogous investigation for stature,
because in this case the increase might simply be ascribed to the better
nutrition of most of the north and central European immigrants after
their immigration into this country.
There is another hypothesis which might account for the observed changes
of type. If it were assumed that among the descendants of immigrants
born in America there are an appreciable number who are in reality
children of American fathers, not of their reputed fathers, a general
assimilation by the American type would occur. Socially this condition
is not at all plausible; but, on account of the importance of the
phenomenon that we are discussing, it should be considered. I do not
think that any of the observations that have been made are in favor of
this theory. The changes that occur in the Bohemians who arrive here as
young children, the different directions of the changes in distinct
types, particularly the shortening of the head of Bohemians and of
Italians, do not favor the assumption. Furthermore, if the modifications
were due to race-mixture, the similarity between fathers and
American-born children should be less than the similarity between
fathers and foreign-born children, but there is no indication that this
is the case.
This hypothesis is also shown to be untenable by the comparisons of
fathers and mothers with their own foreign-born children. These
comparisons show that the differences are the same in the case of
fathers and children, and of mothers and children; so that obviously the
same conditions must control the relations between fathers and their
children, and mothers and their children. In other words, the fathers
must be considered as the true fathers of their children.
Earnest advocates of the theory of selection might claim that all these
changes are due to the effects of changes in death-rate among
foreign-born and American-born; that either abroad or here individuals
of certain types are more liable to die, and that thus these changes are
gradually brought about. On the whole, it seems to my mind, the burden
of proof would be entirely on those who claim such a correlation between
head-index, width of face, etc., and death-rate,—a correlation which I
think is highly improbable, and which could be proposed only to sustain
the theory of selection, not on account of any available facts. I grant
the desirability of settling the question by actual observations; but,
until these are available, we may point out that the very suddenness of
the changes after immigration, and the absence of changes due to
selection by mortality among the adult foreign-born, would require such
a complicated adjustment of cause and effect in regard to the
correlation of mortality and bodily form, that the theory would become
improbable on account of its complexity.
It would be saying too much to claim that all the distinct European
types become the same in America, without mixture, solely by the action
of the new environment. First of all, I have investigated only the
effect of one environment, and there is every reason to believe that a
number of distinct types are developing in America; but we will set
aside this point, and discuss only our New York observations. Although
the long-headed Sicilian becomes more round-headed in New York, the
round-headed Bohemian and Hebrew more long-headed, the approach to a
uniform general type cannot be established, because we do not know yet
how long the changes continue, and whether they would all lead to the
same result. I confess, I do not consider such a result as likely,
because the proof of the plasticity of types does not imply that the
plasticity is unlimited. The history of the British types in America, of
the Dutch in the East Indies, of the Spaniards in South America, favors
the assumption of a strictly limited plasticity. Certainly our
discussion should be based on this more conservative basis until an
unexpectedly wide range of variability of types can be proved. It is one
of the most important problems that arise out of this investigation, to
determine how far the instability or plasticity of types may extend.
Whatever the extent of these bodily changes may be, if we grant the
correctness of our inferences in regard to the plasticity of human
types, we are necessarily led to grant also a great plasticity of the
mental make-up of human types. We have observed that features of the
body which have almost obtained their final form at the time of birth
show modifications of great importance in new surroundings. We have seen
that others which increase during the whole period of growth, and are
therefore subject to the continued effect of the new environment, are
modified even among individuals who arrived here during their childhood.
From these facts we must conclude that the fundamental traits of the
mind, which are closely correlated with the physical condition of the
body, and whose development continues over many years after physical
growth has ceased, are the more subject to far-reaching changes. It is
true that this is a conclusion by inference; but if we have succeeded in
proving changes in the form of the body, the burden of proof will rest
on those who, notwithstanding those changes, continue to claim the
absolute permanence of other forms and functions of the body.
In order to gain a correct understanding of the importance of changes in
the frame of the human body, it seems desirable to view the type of
modern man from a somewhat different standpoint.
It is quite a number of years since Fritsch, in his studies of the
anthropology of South Africa, pointed out that a peculiar difference
exists in the form of the body of the Bushman and the Hottentot as
compared to that of Europeans, in that the former exhibit slenderer
forms of the bones, that the bone is very solid in its structure; while
in the European the skeleton appears heavier, but of more open
structure. Similar differences may be observed in a comparison between
the skeletons of wild animals and those of domesticated animals; and
this observation has led to the conclusion that the Bushmen are in their
physical habitus to a certain extent like wild animals, while the
Europeans resemble in their structure domesticated animals.
This point of view—namely, that the human race in its civilized forms
must be compared, not with the forms of wild animals, but rather with
those of domesticated animals—seems to me a very important one; and a
somewhat detailed study of the conditions in which various races are
found suggests that at the present time, even among the most primitive
types of man, changes incident to domestication have taken place almost
all over the world.
There are three different types of changes due to domestication which
must be clearly distinguished. On the one hand, the bodies of
domesticated animals undergo considerable transformations, owing to the
change in nutrition and use of the body. On the other hand, selection
and crossing have played an important part in the development of races
of domesticated animals.
Some changes of the former class are due to the more regular and more
ample nutrition; other changes are due to modifications of the kinds of
food which the domesticated animal uses when compared with the wild
animal of the same species; still others are due to the different manner
in which the muscular and the nervous systems are put into use. These
changes are not quite the same among carnivorous and among herbivorous
animals. The dog and the cat, for instance, are fairly regularly fed
when they are found in domestication; but the food which is given to
them is of a quite different character from the food which the wild dog
and cat eat. Even among people whose diet consists almost entirely of
meat, dogs are generally fed with boiled meat, or rather with the
boiled, less nutritious parts of animals; while, among other tribes
which utilize to a great extent vegetable food, dogs are often fed with
mush and other vegetable material. The same is true of our cats, whose
diet is not by any means entirely a meat diet. The exertions which wild
carnivorous animals undergo to obtain food are incomparably greater than
those of domesticated carnivorous animals; and it is obvious that for
this reason the muscular system and the central nervous system may
undergo considerable changes.
The muscular exertions of herbivorous animals, so far as they are fed on
pastures, are not so materially changed. The grazing habits of cattle
and sheep in domestication are about the same as the grazing habits of
wild animals of the same class; but the rapid movements and the
watchfulness required for protecting the herd against carnivorous
animals have completely disappeared. Stable-fed animals live under
highly artificial conditions, and material changes may occur in them.
I think the changes due to these causes may be observed in the oldest
types of domesticated animals, such as are found in the neolithic
villages of Europe, in which native European species appear in
domesticated form (Keller). They may also be observed in the dogs of the
various continents, which differ markedly from the wild species from
which they are derived. Even the Eskimo dog, which is a descendant of
the gray wolf and still interbreeds with the gray wolf, differs in
bodily form from the wild animal (Beckmann). Modifications may also be
observed in newly domesticated animals, like the Chukchee reindeer,
which differs in type from the wild reindeer of the same area (Bogoras).
I think it very unlikely, judging from our knowledge of the methods of
domestication of tribes like the Eskimo and Chukchee, that any material
amount of selection has contributed to the modifications of form which
are found in these races of primitive domesticated animals. Their
uniformity is still fairly well marked, although they have assumed types
different from the wild species.
A more marked differentiation of domesticated forms does not seem to
occur until man begins to select and to isolate, more or less
consciously, particular breeds. Opportunity for such isolation has been
the greater, the older the domestication of any particular species. We
find, therefore, that the number of distinct breeds have come to be
greatest in those animals which have been under domestication for the
longest periods.
The number of varieties of domesticated species has also been increased
by unintentional or intentional crossing of different species, from
which are derived many breeds whose ancestry it is often so difficult to
unravel.
It appears, therefore, that there are three distinct causes which bring
about the development of different types in domesticated animals: first,
the influence of change of nutrition and mode of life; secondly,
conscious selection; and, thirdly, crossing.
Among these causes, the first and the third have been most strongly
active in the development of the races of man. The condition of the
tribes of man the world over is such, that there are only very few whose
mode of nutrition is analogous to that of wild animals, and a
consideration of the stages of human culture shows that similar
conditions have prevailed for a long period. I think we may safely say
that in all those cases in which man practises agriculture, when he is
the owner of herds of domesticated animals which are used for food, the
food-supply has become regular, and is obtained by an application of the
muscular system in highly specialized directions. Examples of this
condition are, for instance, the central African negroes, who have their
gardens near their villages, the cultivation of the gardens being
essentially the work of the women, while the men are engaged in various
specialized industrial pursuits. Neither is the manner of the use of the
body which is applied by wild animals for protection against enemies
found among these tribes. The manner of combat is one in which muscular
strength alone is not decisive, but where excellence of weapons and
strategy count as much as mere strength and agility. The conditions
among the American agricultural Indians of the Mississippi Valley or of
those of the South American forests are similar in character.
As an example of a pastoral people among whom considerable regularity in
nutrition obtains, we might mention the reindeer-breeders of Siberia or
the cattle-breeders of Africa.
We know, of course, that among all these people, periods of starvation
occur, due to a failure of the crops or to epidemics in the herds; but
the normal condition is one of fairly regular and ample food-supply.
The conditions among fishing tribes are not very different; and we find
that, owing to methods of storing provisions, and to the superabundance
of food-supply obtained in one season and sufficient to last for the
rest of the year, the nutrition of these people is also fairly regular.
In this case, also, the kind of muscular exertion required for obtaining
food is specialized, and differs from that required from the simple
pursuit of game.
The only modern tribes among which the effects of civilization on bodily
activities are slight are those who, like the Bushmen of South Africa,
the Australians, the Eskimo of Arctic America, the Veddahs of Ceylon,
obtain their livelihood by the constant, daily-repeated pursuit of
animals, or by the gathering of plants or small invertebrates which grow
scattered over a wide area.
Connected with these conditions are also the characteristic selections
of food-stuffs by different tribes, such as the exclusive meat diet of
some tribes (perhaps most pronounced among the Eskimo) and the exclusive
vegetable diet of others, well developed, for instance, in southern
Asia. Both of these have, in all probability, a far-reaching effect upon
the bodily form of these races.
The second group of causes which is most potent in developing distinct
races of domesticated animals—namely, conscious selection—has probably
never been very active in the races of man. We do not know of a single
case in which it can be shown that intermarriage between distinct types
of the same descent was prohibited; and whatever selection there may
have been in the development of primitive society seems to have been
rather that type of natural selection which encourages the mating of
like with like, or such intricate selection as is due to the social laws
of intermarriage, which prevented intermarriages of relatives of certain
grades, and often also of members of different generations. Thus a very
common form of marriage restriction brings it about that among certain
tribes the children of brother and sister intermarry, while the children
of brothers and the children of sisters are not allowed to intermarry.
Similar restrictions are found in great number, and may possibly have
had a certain selective effect, although their operation can hardly be
assumed to have had very marked results upon the form of the human body
(Pearson).
In some cases social laws have had the indirect effect of perpetuating
distinctions between separate parts of a population, or at least of
retarding their complete amalgamation. This is the case where laws of
endogamy relate to groups of distinct descent, and may be observed, for
instance, among the castes of Bengal, where the low castes are of the
characteristic South Indian type, while the highest castes preserve the
type of the tribes of northwestern India (Risley and Gait). The numerous
intermediate castes show, however, that the laws of endogamy, even where
they are as stringent as those of India, cannot prevent blood-mixture.
Whether or not in extreme cases endogamy in small groups, as among the
ancient Egyptians, has led to the development of well-defined types, is
a question that cannot be answered; but it is certain that none of these
types, when found in a large population, have survived.
The third element of domestication, on the other hand, has probably been
very important in the development of the races of man. Crossings between
distinct types are so markedly common in the history of primitive
people, and so markedly rare in the history of wild animals, that in
this case the analogy between domesticated animals and man becomes very
clear. Cases of hybrid forms in nature are almost everywhere rare;
while, as I have pointed out before, domesticated animals have been
crossed and recrossed without end. Crossings between the most distinct
types of man are also of very common occurrence. As an instance, I might
mention the intermarriages between the Hamitic tribes of the Sahara and
the negro tribes of the Soudan (Nachtigal); the mixtures between the
Negritos and Malay, which are of such common occurrence in the Malay
Peninsula (Martin), and which are probably to a great extent the cause
of the peculiar distribution of types in the whole Malay Archipelago;
the mixtures which have taken place in Fiji; that of the Ainu and
Japanese in the northern part of Japan; of European and Mongol in
eastern Europe; not to speak of the more recent mixtures between
European and other races which were incident to the gradual distribution
of the European race over the whole world.
This point of view—namely, the consideration of man as a domesticated
being (with the sole exception, perhaps, of a few hunting tribes)—is
also of great importance for a clear understanding of his mental
activities. The behavior of primitive domesticated animals, like that of
the Eskimo dog or of the Chukchee reindeer, is decidedly different from
the behavior of wild animals. We might perhaps say that the range of
mentality of the domesticated forms seems to be, on the whole, wider,
and this condition increases with increasing degree of domestication.
Cases in which the mental activities of domesticated animals are more
deficient than those of the wild animals, do occur, but are not as
frequent as the reverse cases. An example of this kind is furnished by
sheep.
We are thus led to the conclusion that environment has an important
effect upon the anatomical structure and physiological functions of man;
and that for this reason differences of type and action between
primitive and civilized groups of the same race must be expected. It
seems plausible that one of the most potent causes of these
modifications must be looked for in the progressive domestication of man
incident to the advance of civilization.
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