THE MAKING OF A MAN
Having in this brief preliminary consideration of the fundamental facts
upon which the science of Embryology is based cleared the ground as far
as possible, we may now summarise, in a few simple statements, the point
at which we have arrived in order that we may proceed at once to the
more detailed study of the actual development of the embryo itself.
We are in search of as clear a statement as possible of the origin of
the many and varied characteristics which go to the formation of a human
embryo, and hence to the making of an individual. The variation in these
many characteristics accounts for the differences in individualities. No
two individuals are exactly similar whatever be the standard by which we
estimate them. This is true morally, ethically, and physically. In each
of these spheres there are to be found good, bad, and indifferent
individuals, but whichever they are it is quite obvious that the result
has been brought about by the influence of all the factors of heredity
and environment acting upon the capacities which were originally
implanted in the germ-plasm. An individual is the resultant of the play
upon one man's-worth of human material of all forces which have acted,
or are acting, upon that kind and amount of material. Even though two
children of the same parents be brought up under what are to all
appearances identical circumstances, they differ from the very beginning
from each other and their parents. This is true even of physical
characteristics, and even more markedly in mental features. The fact
is--and it is one which is not sufficiently recognised--that the
formation of an individual from an embryo, the making of a man, is a
biological problem fundamentally.
The following are the principal facts which we have at this stage to
bear in mind.
All living creatures are made of cells, the physical basis of which is
protoplasm. The simplest creatures consist of one such mass of
protoplasm; higher organisms consist of more than one, and often of
millions, in which case they adhere together. Cells multiply by dividing
into two, the protoplasm of the mother-cell giving rise to that of the
daughter-cells. A human embryo, therefore, which is going to give rise
to an adult individual is a community consisting of an enormous number
of cells, the whole of which have descended from one common ancestor, a
single cell known as a fertilised ovum. True, these descendants break up
into many types of cells in order that different functions may be
performed by special tissues, but none of these special cells can do
everything that is necessary for the life of the whole individual; they
can only play their own special small part. They can do nothing towards
continuing the species of the individual. This duty, like others, is
imposed upon one particular group and kind of cells, namely, the
germ-cells, which do nothing else in the animal economy but furnish the
means for the continuity of the race. Although they lie within the
tissues of the embryo, and afterwards of the adult, they take no part in
the life of that embryo or adult. They undergo certain changes in
themselves which are to fit them for their ultimate destiny and
function, but they contribute nothing to the output of energy on the
part of the individual. When these are derived from a female they are
termed "ova"; when from a male they are termed "sperms." They themselves
are neither male nor female, they are merely protected and nourished by
the general mass of cells which constitutes the male and female
individual.
When a male germ-cell or sperm unites with a female germ-cell or ovum,
within the female body, fertilisation of the ovum takes place, and this
gives rise to the fertilised germ-cell from which is to arise first the
germ-cells or direct descendants of itself, and secondly the embryo in
which these germ-cells will come to lie. This happens by the repeated
and continued division of the fertilised germ-cell, a division which
constitutes growth, and which under suitable conditions of nourishment
and protection and exercise will ultimately produce a human being. The
great mass of the cells of this individual, the body or somatic cells,
take no part whatsoever in giving rise to the germ-cells of the next
generation. These are produced from the pre-existing germ-cells, and
from no other source, and it is for this reason alone that the phenomena
of heredity are possible and that one generation is directly continuous
with its predecessors. In fact heredity may be defined as the
relationship which exists between successive generations.
We therefore see that the embryo, or the individual, is formed from one,
and one only, of the first products of the division of the fertilised
germ-cell, the rest of these products forming the other body tissues.
This idea of the continuity of the germ-plasm is the greatest
contribution of modern embryological research. It is quite fundamental,
and no clear understanding of what is involved in the making of a man is
possible without it. It teaches us that the line of ancestry and
heredity is from one generation of germ-cells to another, directly, and
never through the individual from the embryo, which, indeed, is a mere
side product in the continued chain of events. The individual is
practically the trustee of the germ-cells, but not their maker. No
embryo, and no individual, ever made germ-cells; the latter existed
first. The object of the embryo is obviously to protect and nourish the
germ-cells which have been placed within it, so that they may be
available in due time for the production of further germ-cells, and so
for the continuity of the race. Hence it is the all-pervading truth of
natural selection that the interest and survival of the individual is
almost of no account; that of the species or the race being the
paramount consideration.
Once these facts be grasped there is no longer any difficulty in
understanding why the process of reproduction in any given species
always results in the formation of embryos which resemble each other in
all the main characters of their species. It could not be otherwise,
because they come from portions of identically similar material, a
common germ-plasm. In other words, the individual inherits nothing from
its parents. He merely receives in his turn the material inheritance in
the germ-plasm which was there a generation before him.
In so far as there has been no germinal variation he and they will be
similar. Hence the common observation that the child resembles the
parent. True, so he does; but not because he gets his characters from
them, but simply because he and they obtain their characteristics from a
common source. To many this thought will be, perhaps, a new one. It is
one of the most interpreting ideas which science has given us, and in
its absence no real grasp of the origin of the physical, mental, and
other characters if there be any, of the embryo can be understood. The
present writer has elsewhere summarised this thought as follows:--
"Man is composed partly of characteristics, which are derived from
pre-existing germ-cells, and over the possession of which he has no
control whatsoever. Be they good, bad, or indifferent, these
characteristics are his from his ancestry in virtue of his inheritance.
The possession of these characteristics is to him a matter of neither
blame nor praise, but of necessity. They are inevitable."
The embryo then which is to form the individual starts its career with a
certain number of innate germinal characteristics which manifest
themselves in the form of tendencies to grow in this direction or that.
During the period of gestation a good many of these tendencies are well
developed while a good many more only manifest their exact nature in
later life. But it is upon the basis of these tendencies--and upon no
other--that the making of the individual is possible. They represent the
total assets available for the formation of character. Nothing of any
new _kind_ can be added to them.
All that can be done under the best conceivable circumstances is so to
arrange the environment and surroundings of the embryo, and the
subsequent individual, so that these tendencies are acted upon in such a
way that the best are developed, and the worst eliminated. It must be
remembered that it is under the constant action of everything that
constitutes the environment of an embryo that the mass of body-cells
gradually grows into a recognisable human personality.
The question then arises, What are the factors external to the embryo
which cause these germinal tendencies to become active and fully
developed? These factors are those of (_a_) nourishment; (_b_) use, or
exercise; and (_c_) injury. In the case of the human embryo by far the
most important of these three factors is the first. A proper supply of
nourishment and food, that is to say maternal nutrition of adequate
quantity, is sufficient up to the time of birth to cause the inborn
tendencies in all the body-cells gradually to assume the special
characteristics of muscle, bone, gland, nerve, and so forth, which make
the human embryo. After the period of embryonic life is over, the
stimulus of nutrition is still sufficient for some of these body-cells.
Thus we find that the hair, the teeth, the internal ears, and the organs
of reproduction, all grow to their full development in the absence of
any other factor or stimulus than that of nutrition. But, as we also
know, this simple stimulus is not sufficient for most of the other body
tissues to develop properly. They require the additional stimulus of
exercise which, indeed, may be said to begin even in the life of the
embryo. After that it is quite hopeless to expect a healthy embryo to
develop into a fine child unless to the stimulus of nutrition there is
added that of exercise. It is from the varying quantities and qualities
of the three factors of nourishment, exercise, and injury, that part of
the explanation is found for the variation in individuals of the same
family. Starting with a good many of the same inborn tendencies none of
them afterwards receive quite the same kind and amount of these stimuli,
under the action of which they develop. And so we reach the second
point, namely, that, in addition to innate characters certain others are
subsequently acquired by the embryo of the individual in response to
particular stimuli acting from without.
Here we are upon ground which is more or less in our own choice or
control. It is impossible to alter germ-plasm; but it is not impossible
to control the environment in which it exists. To these two groups of
characters, the germinal and those acquired under stimulus, there is to
be added the third group which we have mentioned on a previous page,
namely, those that are usually termed variations. For example, one
occasionally finds that one individual in a family, the parents of
which, and the other members of which, are quite normal, may be born
with six fingers instead of five. Similarly one of a family may have a
variation in the direction of an extraordinary capacity for the
acquisition of knowledge of certain types. Hence the genius in music,
mathematics, memory, morality, and so forth. As we have seen, these
variations are termed spontaneous, to express the fact that we are at
present ignorant of the laws in accordance with which they arise,
though, of course, it is understood that those laws must exist.
We have now surveyed the whole field of the possible origin of the
characters of an embryo, and these may be summed up in the following
tabular statement.
{ A. Inborn Characters--
{ (_a_) Inherited (growing under the stimulus of
{ nutriment).
An Embryo is { (_b_) Variations.
made up of { B. Acquired Characters, obtained
{ (_a_) By nutrition.
{ (_b_) By use.
{ (_c_) By injury.
The differences in individuals with which we are also familiar, are due
to the varying proportions of the characters in the above table, and the
characters themselves are those which constitute all the possibilities
for any given person.
Should the reader doubt this, or be sceptical as to whether the whole of
the making of a man is contained in the above simple scheme, it would
not be difficult for him to convince himself that the statement is a
true one. Let him put down this book and take a sheet of paper and a
pencil. Rule the sheet of paper into three columns, and at the top of
each column place a heading as follows: Inherited; Acquired; and
Variations. Thus:--
+----------------+---------------+-----------------+
| Inherited. | Acquired. | Variations. |
+----------------+---------------+-----------------+
| | | |
| | | |
| | | |
+----------------+---------------+-----------------+
Let him then proceed to think of as many definite characteristics of his
own as he possibly can, and then enter these characteristics in the
column which he deems appropriate. It will be found that with the great
majority of characteristics no difficulty will be presented, and it will
be quite impossible to think of anything which is a physical part of
himself, which cannot be placed in one or other of these three
categories. Even though there may be a little difficulty as to which
column should claim the entry, it will be found that this is due rather
to indecision on the part of the reader than to anything else. It is not
because he can imagine any other origin for the trait which is for the
moment puzzling, but simply because he may be uncertain as to whether it
is an inborn character, or one due to the subsequent action of
circumstances. Thus he will have no difficulty in placing in the first
column such characteristics as the possession of one nose, two eyes, the
colour of his eyes, perhaps the shape of his nose, and so forth, these
all being germinal inherited characters. Equally simple is it to see
that in the second column must be placed such parts of his individuality
as speech, writing, the _size_ of his muscles at the moment, and so
forth. These obviously have resulted from the action of circumstances on
inborn capacities. No embryo can speak or write, though it has within it
the inherited capacity to enable it to learn such things. Finally he may
find it difficult to think of anything to place under the heading of
"Variations"; but, on the other hand, should he happen to be a genius in
music or mathematics, or the possessor of six toes or a black mole on
his arm, these will indicate to him at once that they are of the nature
of "Variations." (It must be remembered, however, that they may be
transmitted to successive generations, in which case they become
germinal characters.)
In a similar way if the reader desires to follow out this analysis of
the characters which make an embryo, and which, therefore, afterwards
comprise the possibilities of an individual from the point of view of
the stimuli under which they are developed, he may easily do so. Another
sheet of paper similarly divided into three columns with the headings
"Nutrition, Use, and Injury," will enable him to see how his individual
characteristics have attained their present development as the result of
one or other of these stimuli acting upon the germinal or inherited
tendencies. Without going into detail in this matter one may simply note
that under the heading of "Injury" will come all those parts of himself
of which he has become possessed as the result of disease or accident,
whether this be physical, mental, or moral.
Now we have completed what was necessary to arrive at our conclusion of
what it is that goes to the making of an embryo, and therefore of a
human being--a personality. The conclusion is that every characteristic
which it is possible for an individual under any circumstances
whatsoever to possess is traceable ultimately to the action which takes
place between his inherited tendencies and his natural environment. This
environment, whether it be physical, mental, moral, ethical, spiritual,
or whatever other can be imagined, can only produce the whole individual
by means of acting upon what is already present. To that material
nothing can be added _except in the environment_; from that material
nothing can be taken away; the most that can be done in this direction
is to hinder its growth by suitable procedures. Hence the truth of the
phrase that "education is nothing more than the giving or withholding of
opportunity." Hence it is so entirely true that it is impossible to make
a silk purse out of a sow's ear, or to gather grapes from thorns. The
importance of thoroughly realising these simple facts of embryology
should at this stage be obvious. They constitute possibly the most
important lesson which is demanding attention at the hands of modern
teachers, parents, and sociologists.
One further word before we leave this part of our subject. It is obvious
that of our total characteristics some are acquired and some are
inherited, and the question then arises, How much is inherited in an
embryo or individual, and therefore unavoidable, and how much acquired?
It would be beyond the scope of our subject in this place to enter into
detail in this matter, but it would not be right to pass the question by
without pointing out that a careful analysis of individual
characteristics will show that under the heading of "Inherited" will be
found principally the physical traits. When the reader comes to estimate
his mental and moral characteristics, a very few moments' careful
thought will prove most conclusively to him that these must be entered
up under the heading of "Acquired." If it were not so progress in those
directions would be practically hopeless. But plain as is this truth, it
is one which is far from being realised by many well-educated people.