degree of excitement could be kept up, mankind would enjoy continual
health. But it is difficult, if not impossible, to regulate the
action of the exciting powers in this equable manner, and if their
action is increased, the first effect they produce on the functions
is to increase them, and the next is, to render them disturbed or
uneasy; or, in other words, to bring on diseases of increased action,
or what have been called inflammatory or phlogistic, both of which
terms are improper, as they convey false ideas, and are connected
with erroneous theories: Dr. Brown has given the name of sthenic to
these diseases, from their consisting in increased strength or
action, and this is certainly a more appropriate term. On the
contrary, when the action of the exciting powers is diminished more
than is natural, the functions become languid and disturbed, and by a
still further decrease of the action of these powers, they become
irregular and inordinate. This state of the body, which is opposite
to the former, Dr. Brown has denominated asthenic.
But the stimulant powers may act so powerfully, and exhaust the
excitability to such a degree, that they may overstep the bounds of
sthenic or inflammatory disease and bring on debility. Debility may
therefore arise either from the stimuli acting too weakly, or from a
deficient excitability, while the stimulus is not deficient. Debility
produced in the former manner is called direct debility, and in the
latter indirect debility.
To explain this more clearly, let us take a common instance. If a
person by any means be deprived of the proper quantity of food, he
will feel himself enfeebled, and the functions will gradually grow
more and more languid, and at last become irregular, and be performed
with pain. This state is called direct debility. Here is excitability
enough, and even too much, for it has accumulated by the subtraction
of a stimulus; but here is a deficiency of excitement from defect of
stimulus.
If now we suppose that a person, in good health, begins to take a
greater quantity of food than usual, and adds a quantity of wine, all
the functions will at first be increased in vigour, but at last they
will be irregularly performed, and inflammation, with other symptoms
of too great excitement, will be the consequence. This state is
called sthenic diathesis or disease. But if the stimulant power be
pushed still further, the excitability will become gradually
exhausted, till at last there will be too little to produce the
healthy actions, even though there may be plenty of stimulus. This
state of asthenic diathesis is called indirect debility, because it
is not produced by directly subtracting the powers which support
life, but indirectly, by over stimulating. An instance of this latter
state is afforded by that debility which is the consequence of
intoxication.
There is a state however between perfect health and disease, which is
called predisposition; and in which, though the functions are
undisturbed, the slightest cause will bring on disease. Strictly
speaking, there is perhaps only one point, or one degree of
excitement, at which the health is perfect: the first alterations
from this point, on either side, are scarcely perceptible, but if the
morbid causes be continued, the functions will become gradually more
and more disturbed, till at last they become so uneasy or painful
that they are termed disease.
In order to render what has been said still more plain, it may be
proper to make use of an illustration by means of numbers: we must
recollect however that it is merely for the sake of illustration, for
we have not data to enable us to reduce either the excitability, or
excitement, or stimulus, to numerical calculation; if we could do
this, the science of medicine would be perfect, and we could cure
diseases as easily as we could perform any chemical or philosophical
experiment. A very principal object however is to understand the
nature of predisposition, and the kind of diathesis, whether sthenic
or asthenic, to which it inclines: this not only throws light on the
nature of the disease, but affords us the only means of preventing
it. When a slight uneasiness or predisposition is felt, it is almost
impossible to say from our feelings whether it leads to a sthenic or
an asthenic state: here we must be guided chiefly by the exciting
powers. If we find that these have acted too powerfully; that is, if
we have lived freely, been exposed to heat, and perhaps indulged in
some of the unnatural stimuli, such as wine and spirits; and
particularly if we previously to the present time perceived the
functions to go on with more vigour, our spirits and strength
greater, before we experienced the slight disturbance of which we
complain, we are verging towards sthenic or inflammatory disease, and
therefore to prevent the disease we ought immediately to diminish the
action of the exciting powers; the quantity of food ought to be
diminished, wine and other liquors abstained from, heat carefully
avoided; and even the quantity of blood in the circulating system
diminished, if the habit is full and the pulse strong.
On the contrary, if the exciting powers have acted more feebly than
is natural; that is, if we have lived on a less nourishing diet, or
have taken it in less quantity; if we have been long exposed to cold,
without alternating with heat, and other debilitating causes; and if
at the same time we find the vigour of the functions diminished,
though they are not yet become much disturbed, we are verging towards
asthenic disease. To prevent which, we must take a more nutritious
diet, and join a portion of wine, and perhaps take some tonic
medicines. This however ought to be done gradually, for fear of
exhausting the excitability, which in these cases is morbidly
accumulated.
It must be evident that the great difficulty here is to determine the
nature of the predisposition; for if we make a mistake, instead of
preventing, we shall accelerate the disease. For instance, the first
slight disturbance of the functions which rises from a sthenic state,
often resembles those verging towards a state of debility or
asthenia. I have seen various instances arising from plethora, or a
sthenic state, where the patient complained of depression of spirits,
and inability to move; and, in short, from his own account was
labouring under asthenic diathesis: but by inquiring carefully into
the action of the exciting causes, examining minutely the state of
the pulse and of the functions, I have been convinced that the
depression of spirits which he felt, and other symptoms of weakness,
depended on fullness, and they have been quickly removed by lowering
the diet, administering a laxative, or taking a little blood: whereas
if, apprehending from the symptoms that he had laboured under
debility, I had ordered him a more generous diet and tonic remedies,
an inflammatory disease would have been the consequence, which might
have terminated in death.
I have seen various instances where patients have complained of this
unusual depression, and inability to move: they have shown me
prescriptions in which the stimulant or tonic plan was recommended,
but instead of any alleviation the symptoms had become worse from
their use. This hint was generally sufficient, for if the disease of
predisposition had been asthenic, cordials and tonics ought to have
relieved it: if, on inquiry, I found the exciting powers had acted
too powerfully, I then, without hesitation, had recourse to the
debilitating plan, and with the greatest certainty of success. Before
I viewed diseases and their causes in this way, I must confess that I
often felt great hesitation in practice; and judging merely from
symptoms, which are frequently very fallacious, the operation of a
remedy often disappointed me, and I could not pretend to predict the
event with the certainty that I now can. This observation is of the
greatest consequence in the cure both of predisposition and of
disease. Though excitement regulates all the phenomena of life, yet
the symptoms of diseases which either its excess or deficiency
produces, do not of themselves lead to any proper judgment respecting
it. On the contrary their fallacious appearance has proved the source
of infinite error.
As excitement both depends on exciting powers and excitability, it is
evident that when a middle degree of stimulus acts upon a middle
degree of excitability, the most perfect effect will be produced.
This point, could we ascertain it, might be called the point of
health. For the sake of illustration, we may suppose that the
greatest excitability of which the living body is capable is 80
degrees: this may be supposed to be the excitability possessed by the
body at the commencement of its life, because no part has then been
wasted or exhausted by the action of stimuli. Now, if we suppose a
scale of excitability to be formed, and divided into 80 equal parts
or degrees, the excitability will be wasted or exhausted in
proportion to the application of stimuli, from the beginning to the
end of the scale. One degree of exciting power applied takes off one
degree of excitability, and every subsequent degree impairs the
excitability in proportion to its degree of force. Thus a degree of
stimulus or exciting power equal to 10 will reduce the excitability
to 70, 20 to 60, 30 to 50, 40 to 40, 50 to 30, 60 to 20, 70 to 10, 80
to 0; and, on the contrary, the subtraction of stimulant power will
allow the excitability to accumulate.
[DIAGRAM]
The range of good health is ranked from 30 to 50 degrees in the
scale; for perfect health, which consists in the middle point only,
or at 40 degrees, rarely occurs; in consequence of the variation of
the stimuli to which man is continually exposed, such as meat and
drink, heat, exercise, and the emotions of the mind, the excitement
commonly fluctuates between 30 and 50 degrees, and yet no particular
disturbance of the functions takes place. But when at these points,
30 or 50, predisposition commences, the slightest debilitating cause
in the former case, and the slightest stimulating cause in the
latter, brings on disease, in which the functions begin to be
disturbed in various ways, and this disturbance is always in
proportion to the hurting powers which have produced the disease, and
the delicacy or importance of the part affected.
The effect produced on the excitability by any stimulus, must
evidently be in a ratio compounded of the degree of excitability and
the force of the stimulus. The same stimulus will produce greater
contractions upon a fibre that is more irritable than upon one which
possesses less irritability; and the irritability or excitability of
the fibre being given, or remaining the same, the contraction will be
in proportion to the strength of the stimulus. Hence it is evident,
that the effect or excitement must be in a ratio compounded of the
exciting powers and excitability.
Sthenic diathesis and disease is caused by the operation of different
exciting powers, which produce too great a degree of excitement in
the system: this at first increases all the functions, and, when
increased, produces a disturbance and inordinate action of them,
which is communicated to the whole body. In diseases of this kind
there is often an appearance of debility, but this is extremely
fallacious, and arises from the disturbed state of the different
functions. Hence it is evidently of the utmost consequence to
ascertain carefully whether this debility is real, or the effect of
asthenic disease: or whether it is owing to the disturbance of the
functions by over stimulating, and in this case fallacious; for
should a sthenic disease be treated by stimulants and cordials, the
effect would be an aggravation of all the symptoms, and a much higher
degree of disease.
Asthenic diathesis and disease is brought on by the excitement of the
system being diminished: and this may proceed either from a
diminution of common stimulant powers, while the excitability is
sufficiently abundant, or it may proceed from an exhausted
excitability, while the stimulus is sufficiently abundant. The former
is called direct, and the latter indirect debility. The exciting
causes therefore of asthenic disease, first impair the functions,
then occasion a disturbed or inordinate action of them, giving many
of them a false appearance; some of them, for instance, appear to be
increased, for in hysteria and epilepsy, which are both diseases of
debility, the action of the muscles seems to be preternaturally
increased; but this depends chiefly on the accumulated excitability,
which gives such a degree of irritability to the system, that the
smallest irritation, whether external, such as heat, exercise, &c. or
internal, as emotions of the mind, excite a strong spasmodic action,
which brings on the symptoms of epilepsy and hysteria. This
inordinate action however soon exhausts the morbid excitability, and
thus suspends itself, a sleep often follows, from which the patient
wakes with only a general sense of languor and debility: but as the
same cause still remains, the excitability of the body again becomes
morbidly accumulated, and thus the slightest stimulus produces a
recurrence of the fit, and the tendency to return will increase with
its recurrence, so that at last the slightest imaginable cause will
produce it, on account of the power of habit and association.
Gout likewise appears like a sthenic disease, and in inflammation
takes place, which resembles pleurisy or peripneumony; but this
symptom is fallacious, for it depends on debility, and is only to be
cured by means, which in pleurisy and peripneumony, would produce
death.
Hence it must be evident that those phenomena of diseases, which we
call symptoms, are generally fallacious; but this may be owing to our
imperfect knowledge of the animal economy, so that we are not able to
explain or understand the manner in which they are produced: we ought
however carefully to guard against being misled by them in practice.
The great difficulty is to distinguish the nature of the disease,
whether it is sthenic or asthenic, or whether it depends on too great
excitement, or on debility; for this being once clearly ascertained,
we proceed with certainty in our mode of treatment, instead of the
random practice, which must be the consequence of not taking a proper
view of the laws of life, and the causes of diseases.
The nature of the disease may be generally ascertained, by attending
to the habits of the patient, and the manner in which he has lived,
as well as to the state of the pulse; but in cases where these
circumstances do not render it clear, it may be ascertained, beyond a
doubt, by a trifling degree of stimulus, as, for instance, by any
cordial, as a little wine or spirits. If the disease be of an
inflammatory or sthenic kind, the symptoms will be aggravated, and
the cordial will not produce its usual pleasant effects on the
system; but on the contrary, if the nature of the disease be
asthenic, then the usual pleasant effects of the cordial will be
perceived, and the pain and other symptoms will be alleviated. This
trial, which is soon made, and without danger, will determine our
plan of cure, and we can then proceed with the most perfect
certainty. Thus you will see that this view we have taken leads to a
very different and much more rational plan of practice than is
generally followed, in which the most judicious physicians confess
that they have no clue to guide them; and complain that the science
of medicine consists merely in a number of insulated facts, not
connected by any theory: that they merely prescribe a remedy because
they have seen it of use in an apparently similar state, but that
they have no certainty of its producing a similar effect in the cases
in which they prescribe it. This all depends on trusting to the
fallacious appearance of symptoms, and not having taken a proper view
of the laws of life, or the manner in which the exciting powers act
on living bodies.
After these observations on the diagnosis, or the method of
distinguishing the nature of diseases, I shall proceed to consider
more particularly the nature of sthenic diseases, and the methods of
curing them, which will occupy the remainder of our time this
evening.
The powers or causes, which by their action produce inflammatory or
sthenic diseases, are, first, heat, which is a very frequent cause,
particularly when it succeeds cold; for the cold accumulates the
excitability, and then renders the whole body, or a part, more liable
to be affected by the heat afterwards applied. In this way is
produced rheumatism, catarrh, or, as it is commonly called, a cold,
and peripneumony. These complaints have been often attributed to
cold, but I believe that there never was a well attested instance
where cold alone, without being either followed by heat or some other
stimulus, produced a real sthenic, or inflammatory disease. This is
not merely a distinction, it is a circumstance of the utmost
importance, because it influences the mode of practice to be pursued.
Heat is one of the exciting or stimulant powers which support life,
and one of the most powerful of these stimulants; but cold is only a
diminution of it: how then can this produce a sthenic state, or a
state of too high excitement? The blood is one of the exciting
powers, which, by its continual circulation supports life; but surely
if we abstracted a quantity of this fluid from the body, no person
will be bold enough to say, that we by that means should produce an
inflammatory disease. Cold renders the body more liable to be
affected by heat, or any other stimulus applied, but does not of
itself produce any stimulant or inflammatory effects.
To see more clearly the manner in which cold acts, let us inquire how
it produces or contributes towards the production of catarrh. When we
go into the cold air, at every respiration we take a quantity of it
into the lungs, which brushes over the surface of the mucous membrane
that lines the nostrils and trachea, and thus, robbing them of their
heat, allows the excitability to accumulate. But we feel no fever, no
sense of tightness or stuffing, nor any other symptom of catarrh, so
long as we continue in the cold. If however we afterwards go into a
warm room, and particularly near a fire, we receive by the act of
respiration the warm air into those very parts which have been
previously exposed to cold, and whose excitability is consequently
accumulated. The first effect we perceive is a glow of the parts,
which is by no means unpleasant, this however increases; and, in the
course of half an hour or an hour, a sense of dryness and huskiness
comes on, with a sensation of stuffing in the nostrils, and a
tendency to a short dry cough: often likewise, if the exposure to
cold has been considerable, and the heat afterwards applied great and
sudden, we experience a shivering, and other symptoms of fever. These
symptoms are all increased by taking into the stomach any liquid that
is either of warm temperature or stimulating quality, or particularly
both; we spend a restless night, and awake with all the symptoms of a
catarrh, or cold, as it is improperly called. For it is evidently an
inflammatory fever, and can be speedily cured by the debilitating
plan, and particularly by keeping in a moderately cool place, where
the temperature is equable, and not subject to alternations of heat
and cold.
But how easily might this complaint have been avoided, were the
person subject to it acquainted with its real nature, and the manner
in which it is brought on. When we come out of a very cold
atmosphere, we should not at first go into a room that has a fire in
it; or, if this cannot be well avoided, we should keep for a
considerable time at as great a distance from the fire as possible,
that the accumulated excitability may be gradually exhausted by the
moderate and gentle action of heat; and then we may bear the heat of
the fire without any danger; but above all, we should refrain from
taking warm or strong liquors while we are hot. In confirmation of
this opinion, numerous instances might be brought, where catarrh was
cured merely by exposure to cold.
When a part of the body only has been exposed to the action of cold,
and the rest kept heated; if, for instance, a person in a warm room
has been sitting so that a current of air, coming through a broken
window, has fallen upon any part of the body, that part will soon be
affected with an inflammation, or what is called a rheumatic
affection. In this case, the excitability of the part exposed to the
action of the cold, becomes accumulated, and the warm blood, rushing
through it, from every other part of the body, excites an
inflammation.
Thus catarrh and rheumatism are inflammatory complaints, or depend on
too great a degree of excitement, and are to be cured by lowering the
excitement, or diminishing the action of the exciting powers; by
bleeding, purging, low diet, and particularly keeping in a moderately
cool place; and these complaints will be as speedily and certainly
cured by these methods, properly and judiciously persevered in, as a
slight cut or wound will be healed by what surgeons call the first
intention.
There are complaints which resemble these, but whose nature, however,
is very different, and which require a very different mode of
treatment. After a part has been long affected with rheumatic
inflammation the excitability of the muscular fibres becomes so far
exhausted, that a state of indirect debility takes place, and an
inflammation, accompanied with pain and redness, which is very
different from that I formerly described, as it depends upon a
debilitated or relaxed state of the parts, instead of too great a
degree of excitement. This instance shows strongly the fallacy of
symptoms; but it may be readily distinguished from the inflammatory
rheumatism, by attention to the effects of the exciting causes. The
inflammatory rheumatism is aggravated by heat, hence it is more
violent in bed than at any other time. The latter complaint, however,
is greatly relieved by heat: the warm bath alleviates all the
symptoms; so does a warm bed. It is evident that these diseases,
though attended by the same symptoms, are as opposite, and require as
different modes of treatment as an inflammation of the brain, and a
dropsy. The inflammatory state has been called the acute rheumatism,
and the other, the chronic rheumatism; I would, however, prefer the
terms sthenic and asthenic rheumatism.
In the same manner, there is a catarrh, which is liable to afflict
persons who have often been subject to an inflammatory cold,
particularly persons advanced in years; and this depends on a state
of indirect debility of the parts, the excitability of which has been
exhausted by frequent and violent inflammatory affections. This
complaint, which I would call asthenic catarrh, requires directly
opposite treatment from the inflammatory or sthenic catarrh. The
latter is aggravated by heat, but relieved by a cool temperature.
Warm air is peculiarly grateful to those who are afflicted with the
former, and if they go into a cool temperature, they are immediately
seized with cough, and expectoration; for the disease being a disease
of debility, the withdrawing the stimulus of heat, must increase it.
The excitability of the parts is so far exhausted, that it requires a
stimulus even more than natural to keep them in tone: hence persons
labouring under asthenic catarrh, and some species of asthma, which
are only varieties of this disease, find themselves best when exposed
to a warm temperature, but on the heat being diminished, and
consequently the parts relaxed, the cough and difficulty of breathing
immediately come on.