Disease and Its Causes by William Thomas Councilman

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The most obvious inheritance is seen in the case of malformations.
These represent wide departures from the type of the species as
represented in the form. There is no hard and fast line separating the
slight departures from the normal type known as variations and
mutations, from the malformations. Certain of the malformations known
as monstrosities hardly represent the human type. These are the cases
in which the foetus is represented in a formless mass of tissue, or
there is absence of development of important parts such as the nervous
system or there is more or less extensive duplication of the body.
There has always been a great deal of popular interest attached to the
malformations owing to the part which maternal impressions are
supposed to play in their production. In this, some striking
impression made on the pregnant woman is supposed to affect in a
definite way the structure of the child. The cases, for instance, in
which a woman sees an accident involving a wound or a loss of an arm
and the child at birth shows a malformation involving the same part.
There is no association between maternal impressions and
malformations, although there have been many striking coincidences.
All malformations arise during the first six weeks of pregnancy known
as the embryonic period, in which the development of the form of the
child is taking place, and during which time there is little
consciousness of pregnancy. Maternal impressions are usually received
at a later period, when the form of the child is complete and it is
merely growing. It must be remembered also that there is neither
nervous nor vascular connection between the child in the uterus and
the mother, the child being from the period of conception an
independent entity to which the mother gives nutriment merely. Of
course, as has been said, the mother may transmit to the child
substances which are injurious, and in certain cases parasites may
pass from the mother to the foetus. The same types of malformations
which occur in man are also seen in birds, and it would require a more
vigorous imagination than is usual to believe that a brooding hen
could transmit an impression to an egg and that a headless chick could
result from witnessing the sacrifice of an associate. The idea of the
importance of maternal impressions in influencing the character of the
offspring is a very old one, a well-known instance being the sharp
practice of Jacob's using peeled wands to influence the color of his
cattle. In regard to coincidences the great number of cases in which
strong impressions made on the mind of the pregnant mother without
result on the offspring are forgotten. The belief has been productive
of great anxiety and even unhappiness during a period which is
necessarily a trying one, and should be dismissed as being both
theoretically impossible and unsupported by fact.

The malformations are divided anatomically into those characterized,
first, by excess formation, second, by deficient formation, third, by
abnormal displacement of parts. They are due to intrinsic causes which
are in the germ, and which may be due to some unusual conditions in
either the male or female germ cell or an imperfect commingling of the
germinal material, and to extrinsic causes which physically, as in the
nature of a shock or chemically as by the action of a poison, may
affect the embryo through the mother. Malformations are made more
numerous in chickens by shaking the eggs before brooding. A number of
malformations are produced by accidental conditions arising in the
environment; for instance, the vascular cord connecting mother and
child may become wound around parts constricting them or even cutting
them off, and the membrane around the child may become adherent to
certain parts and prevent the development of these. The extrinsic
causes are more operative the more unfavorable is the environment of
the mother. Malformations are more common in illegitimate children
than in legitimate and more common in alcoholic mothers; there is an
unfavorable environment of poverty in both cases, added to in the
latter and usually in the former by the injurious action of the
alcohol.

The more extensive malformations have no effect on heredity, because
the subjects of them are incapable of procreation. The malformations
which arise from the accidents of pregnancy and which are compatible
with a perfectly normal germ are in the nature of acquired
characteristics and are not inherited. Those malformations, however,
which are due to qualities in the germinal material itself are
inherited, and certain of them with remarkable persistence. There are
instances in which the slight malformation consisting in an excess of
fingers or toes has persisted through many generations. It may
occasionally lapse in a generation to reappear later. In certain
cases, notably in the bleeders, the inheritance is transmitted by the
female alone, in other cases by the sexes equally, but there are no
cases of transmission by the male line only. It is evident that when
the same malformation affects both the male and the female line the
hereditary influence is much stronger. A case has been related to me
in which most of the inhabitants in a remote mountain valley in
Virginia where there has been much intermarriage have one of the
joints of the fingers missing. There is a very prevalent idea that in
close intermarriage in families variations and malformations often
unfortunate for the individual are more common. All experimental
evidence obtained by interbreeding of animals shows that close
interbreeding is not productive of variation, but that variations
existing in the breed become accentuated. Variations either
advantageous or disadvantageous for the race or individual may either
of them become more prevalent by close intermarriage. It seems,
however, to have been shown by the customs of the human race that very
close intermarriage is disadvantageous.

Eugenics, which signifies an attempt at the betterment of the race by
the avoidance of bad heredity, has within recent years attracted much
attention and is of importance. Some of its advocates have become so
enthusiastic as to believe that it will be possible to breed men as
cattle and ultimately to produce a race ideally perfect. It is true
that by careful selection and regulation of marriage certain
variations, whether relating to coarse bodily form or to the less
obvious changes denoted by function, can be perpetuated and
strengthened. That the Semitic race excels in commerce is probably due
to the fact that the variation of the brain which affected favorably
the mental action conducive to this form of activity, was favorable
for the race in the hostile environment in which it was usually placed
and transmitted and strengthened by close intermarriage. It is
impossible, however, to form a conception of what may be regarded as
an ideal type of the human species. The type which might be ideal in a
certain environment might not be ideal in another, and environment is
probably of equal importance with the material. The eugenics movement
has enormously stimulated research into heredity by the methods both
of animal experimentation and observation, and study of heredity in
man. As in all of the beginning sciences there is not the close
inter-relation of observed facts and theory, but there is excess of
theory and dearth of facts. Certain considerations, however, seem to
be evident. It would seem to be evident that individuals should be
healthy and enabled to maintain themselves in the environment in which
they are placed, but the qualities which may enable an individual
successfully to adapt himself to factory life, or life in the crowds
and strong competition of the city, may not be, and probably are not,
qualities which are good for the race in general or for his immediate
descendants. At present our attempts to influence heredity should be
limited to the heredity of disease only. We can certainly say that
intermarriage between persons who have tuberculosis or in whose
families the disease has prevailed is disadvantageous for the
offspring; the same holds true for insanity and for nervous diseases
of all sorts, for forms of criminality, for alcoholism, and for those
diseases which are long enduring and transmitted by sexual contact
such as syphilis and gonorrhoea. It is of importance that the facts
bearing on the hereditary transmission of disease should become of
general knowledge, in order that the dangers may be known and
voluntarily avoided. No measures of preventive medicine are successful
which are not supported by a public educated to appreciate their
importance, and the same holds true of eugenics. How successful will
be public measures leading to the prevention of offspring in the
obviously unfit by sterilization of both males and females is
uncertain. It is doubtful whether public sentiment at the present time
will allow the measure to be thoroughly carried out. Some results in
preventing unfit heredity may be attained by the greater extension of
asylum life, but the additional burden of this upon the labor of the
people would be difficult to bear. At best such measures would only be
carried out in the lower class of society.

CHAPTER XI

CHRONIC DISEASES.--DISEASE OF THE HEART AS AN EXAMPLE.--THE STRUCTURE
AND FUNCTION OF THE HEART.--THE ACTION OF THE VALVES.--THE PRODUCTION
OF HEART DISEASE BY INFECTION.--THE CONDITIONS PRODUCED IN THE
VALVES.--THE MANNER IN WHICH DISEASE OF THE VALVES INTERFERES WITH
THEIR FUNCTION.--THE COMPENSATION OF INJURY BY INCREASED ACTION OF
HEART.--THE ENLARGEMENT OF THE HEART.--THE RESULT OF IMPERFECT WORK OF
THE HEART.--VENOUS CONGESTION.--DROPSY.--CHRONIC DISEASE OF THE
NERVOUS SYSTEM.--INSANITY.--RELATION BETWEEN INSANITY AND
CRIMINALITY.--ALCOHOLISM AND SYPHILIS FREQUENT CAUSES OF
INSANITY.--THE DIRECT AND INDIRECT CAUSES OF NERVOUS DISEASES.--THE
RELATION BETWEEN SOCIAL LIFE AND NERVOUS DISEASES.--FUNCTIONAL AND
ORGANIC DISEASE.--NEURASTHENIA.

Chronic diseases are diseases of long duration and which do not tend
to result in complete recovery; in certain cases a cause of disease
persists in the body producing constant damage, or in the course of
disease some organ or organs of the body are damaged beyond the
capacity of repair, and the imperfect action of such damaged organs
interferes with the harmonious inter-relation of organs and the
general well-being of the body. The effect of damage in producing
chronic disease may not appear at once, for the great power of
adaptation of organs and the exercise of reserve force may for a time
render the damage imperceptible; when, however, age or the
supervention of further injury diminishes the power of adaptation the
condition of disease becomes evident. Chronic disease may be caused by
parasites when the relation between host and parasite is not in high
degree inimical, as in tuberculosis, gonorrhoea, syphilis, most of the
trypanosome diseases and the diseases produced by the higher
parasites. In certain cases the chronic disease represents really a
series of acute onsets; thus in the case of the parasites there may be
periods of complete quiescence of infection but not recovery, the
parasites remaining in the body and attacking when the defences of the
body are in some way weakened. In such cases there may be temporary
immunity produced by each excursion of the disease, but the immunity
is not permanent nor is the parasite destroyed. There is a further
connection between chronic disease and infection in that the damage to
the organs, which is the great factor underlying chronic disease, is
so often the result of an infection.

The infectious diseases are those of early life; chronic disease, on
the other hand, is most common in the latter third of life. This is
due to the fact that in consequence of the general wear of the body
this becomes less resistant, less capable of adaptation, and organic
injury, which in the younger individual would be in some way
compensated for, becomes operative. The territory of chronic disease
is so vast that not even a superficial review of the diseases coming
under this category can be attempted in the limits of this book, and
it will be best to give single examples only, for the same general
principles apply to all. One of the best examples is given in chronic
disease of the heart.

The heart is a hollow organ forming a part of the blood vascular
system and serving to give motion to the blood within the vessels by
the contraction of its strong muscular walls. It is essentially a
pump, and, as in a pump, the direction which the fluid takes when
forced out of its cavity by the contraction of the walls diminishing
or closing the cavity space, is determined by valves. The contraction
of the heart, which takes place seventy to eighty times in a minute,
is automatic and is due to the essential quality of the muscle which
composes it. The character, frequency and force of contraction,
however, can be influenced by the nervous system and by the direct
action of substances upon the heart muscle. The heart is divided by a
longitudinal partition into a right and left cavity, and these
cavities are divided by transverse septa, with openings in them
controlled by valves, each into two chambers termed _auricle_ and
_ventricle_. The auricle and ventricle on each side are
completely separated.

The circulation of the blood through the heart is as follows: The
blood, which in the veins of the body is flowing towards the heart,
passes by two channels, which respectively receive the blood from the
upper and lower part of the body, into the right auricle. When this
becomes distended it contracts, forcing the blood into the right
ventricle; the ventricle then contracts and sends the blood into the
arteries of the lungs, the passage of blood into the auricle being
prevented by valves which close the opening between auricle and
ventricle when the latter contracts upon its contents. When the
ventricle empties by its contraction the wall relaxes and the back
flow from the artery is prevented by crescentic-shaped valves placed
where the artery joins the ventricle. A similar arrangement of valves
is on the left side of the heart. The pressure given the blood by the
contraction of the right ventricle sends it through the lungs; from
these, after it has been oxygenated, it passes into the left auricle,
then into the left ventricle and from this into the great artery of
the body, the aorta, which gives off branches supplying the
capillaries of all parts of the body. Both of the auricles and both of
the ventricles contract at the same, time, the ventricular contraction
following closely upon the contraction of the auricles. Contraction or
systole is followed by a pause or diastole during which the blood
flows from the veins into the auricles. The work which the right
ventricle accomplishes is very much less than that of the left, and
the right ventricle has a correspondingly thinner wall. The size of
the heart is influenced by the size and the occupation of the
individual being larger in the large individual than in the small, and
larger in the active and vigorous than in the inactive. Generally
speaking, the heart is about as large as the closed fist of its
possessor.

Imperfections of the heart which interfere with its action may be the
result of failure of development or disease. An imperfect heart which
can, however, fully meet the limited demands made upon it in
intra-uterine life, may be incapable of the work placed upon it in
extra-uterine life. Children with imperfectly formed hearts may be
otherwise perfect at birth, but they have a bluish color due to the
imperfect supply of the blood with oxygen, and are known as blue
babies. The condition becomes progressively worse due to the
progressive demands made upon the heart, and death takes place after
some days or months or years, the time depending upon the degree of
the imperfection.

Much of the damage of the heart in later life is due to infection. The
valves of the heart are a favorite place for attack by certain sorts
of bacteria which get into the blood. This is due to the prominent
position of the valves which brings them in contact with all the blood
in the body, the large extent and unevenness of the surface and to the
rubbing together and contact of their edges when closed. At the site
of infection there is a slight destruction of tissue and on this the
blood clots producing rough wart-like projections. The valves in some
cases are to a greater or less extent destroyed, they may become
greatly thickened and by the deposit of lime salts converted into
hard, stony masses. Essentially two conditions are produced. In one
the thickened, unyielding valves project across the openings they
should guard, and thus by constricting the opening interfere with the
passage of blood either through the heart or from it. In the other the
valves are so damaged that they cannot properly close the orifices
they guard, and on or after the contraction of the cavities there is
back flow or regurgitation of the blood. If, for instance, the orifice
of the heart into the aorta is narrowed, then the left ventricle can
only accomplish its work of projecting into the aorta a given amount
of blood in a given time by contracting with greater force and giving
a greater rapidity to the stream passing through the narrow orifice.
This the heart can do because, like all other organs of the body, it
has a large reserve force which enables it, even suddenly, to meet
demands double the usual, and like all other muscles of the body it
becomes larger and stronger by increased work. The condition here is
much simpler than when the same valve is incapable of perfect closure,
or when both obstruction and imperfect closure, are combined as they
not infrequently are. In such cases the ventricle must do more than in
the first case. It must force through the orifice, which may be
narrowed, the amount of blood which is necessary to keep up the
pressure within the aorta and give to the circulation the necessary
rapidity of flow, and also the amount which flows back into the heart
through the imperfectly acting valve. This it can do by contracting
with greater force upon a larger amount of blood, the cavity becoming
enlarged to receive this. Not only may such damage to the valves be
produced, but the muscular tissue of the heart may suffer from
defective nutrition or from the effect of poisons, whether these are
formed in the body as the effect of disease or introduced from
without; or in consequence of disease in the lungs the flow of blood
through them may be impeded, or disease elsewhere in the body, as in
the kidneys may, by increasing the pressure of the blood within the
arteries, throw more than the usual amount of work upon the heart.

The power of the heart in meeting these conditions, however various
they are and however variously they act, seems little short of
marvellous, and it goes on throwing three and one-third ounces of
blood seventy or eighty times a minute into a tube against nine feet
of water pressure, working often perfectly under conditions which
would be fatal to a machine. As long as this goes on the injury is
said to be compensated for; the increased work which the heart is able
to accomplish by the exercise of its reserve force and by becoming
larger and stronger enables it to cope with the adverse conditions.
With increased demand for work there is a gradual diminution of the
reserve force. An individual may be able to carry easily forty pounds
up a hill and by exerting all his force may carry eighty pounds, but
if he habitually carries the eighty pounds, even though the muscles
become stronger by exercise the load cannot be again doubled. The
dilatation of the heart which is so important in compensation is
fraught with danger, because any weakening of the muscle increases the
dilatation, until a point is reached when, owing to the dilatation of
the orifices between auricles and ventricles, the valves become
incompetent to close them.

When the heart is not able to accomplish its work, the effect of the
condition becomes apparent by the accumulation of blood within the
veins and a less active circulation. This affects the nutrition and
the capacity for work of all the organs of the body, and the imperfect
function of the organs may in a variety of ways make still greater
demands upon an already overloaded heart. Other conditions supervene.
The increased pressure within the veins and capillaries due to the
impossibility of the blood in the usual amount passing through or from
the heart increases the amount of fluid in the tissues. There is
always an interchange between the blood within the vessels and the
fluid outside of them; the passage of fluid from the vessels is
facilitated by the increased pressure within them, just as pressure
upon a filtering fluid increases the rapidity of filtration, and the
increase of pressure within veins and capillaries impedes passage of
tissue fluid into them. The fluid accumulates within the tissues
leading to dropsy, or the accumulation may take place in some of the
cavities of the body. The diminished flow of blood through the lungs
prevents its proper oxygenation; this may also be interfered with by
the accumulation of fluid within the air spaces of the lungs.

Every additional burden thrown upon the heart increases the evil. In
women the additional burden of pregnancy may suffice to overcome a
compensation which has been perfect, and the same may result from an
acute attack of disease. Age, diminishing as it does the capacity for
work in all organs, diminishes the compensation capacity of the heart,
and a heart which at the age of forty acts perfectly may break down at
the age of fifty. Compensation may be gained in other ways, as by
reducing the demand made upon the heart by changing the mode of life,
by leading an inactive rather than an active life, by avoiding
excitement or any condition which entails work of the heart. Social
conditions are of great importance; it makes a great difference
whether the unfortunate possessor of such a heart be a stevedore whose
capital lies in the strength of his muscles, or a more fortunately
placed member of society for whom the stevedore works and whose
occupation or lack of occupation does not interfere with the
adjustment of his external relations to the condition of his heart.

Disease of the nervous system does not differ from disease elsewhere.
The system is complex in structure and in function. It consists in
nerves which are composed of very fine fibrils distributed in all
parts of the body and serve the purpose of conduction, and a central
body composed of the brain and spinal cord which is largely cellular
in character; it receives impressions by means of the nerves and sends
out impulses which produce or affect action in all parts. By means of
the organs of special sense, the brain receives impressions from the
outer world which it transforms into the concepts of consciousness.
Many of the impressions which the central nervous system receives from
nerves other than those of special sense and even many of the
impressions from these and the impulses which it sends out do not
affect consciousness. The memory faculty is seated in the brain and
all parts of the brain are closely connected by means of small nerve
fibres. The nervous system plays an important part in the internal
regulation and coordination of all parts of the body, and it is by
means of this that the general adjustment of man with his environment
is effected.

Malformations of the brain, except very gross conditions which are
incompatible with extra-uterine existence, are not very common. At
birth those parts of the brain which are the seat of memory and what
are understood as the higher faculties are very imperfectly developed.
Variations in structure are extremely common, there are differences in
different individuals in the nerves and in the number, size, form and
arrangement of the nerve cells, and so complex is the structure that
considerable variation can exist without detection. The tissue of the
central nervous system has a considerable degree of resistance to the
action of bacteria, but is, however, very susceptible to injury by
means of poisons. Serious injury or destruction of tissue of the brain
and spinal cord is never regenerated or repaired, but adjustment to
such conditions may be effected by reciprocity of function, other
cells taking up the functions of those which were destroyed.

Certain parts of the brain are associated with definite functions;
thus, there are areas which influence or control speech and motion of
parts as the arm or leg, and there are large areas known as the silent
areas whose function we do not know. All activity of the central
nervous system, however expressed, is due to cell activity and is
associated with consumption of cell material which is renewed in
periods of repose and sleep. Fig. 13 shows a nerve cell of a sparrow
at the end of a day's activity and the same after the repose of a
night.

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