is in fact the essence of organic contractility, that a muscle because
it is in contact with a body to which it is not accustomed, instantly
contracts. If the muscles are not irritated by the organs that surround
them and with which they are in relation, it is because habit has
blunted the sensation which arises from this relation. But when these
organs change their modifications, when extracted from the body of the
animal, they become cold, and are afterwards applied to the organic
muscles laid bare, they will make them contract.
Caloric, by its absence which constitutes cold, as by its presence from
which arises heat, can equally excite the muscles and in general all
the organs. At the instant we open the thorax or the pericardium of a
living animal, the heart is agitated with a suddenly increased force;
it is because the air acts upon it, and it passes from the temperature
of the body to another which is different. All the aeriform fluids,
light, all fluids, &c. are stimuli of the muscles. If we see the heart
emptied of blood, the stomach and intestines deprived of the substances
that ordinarily enter them, contract with more or less force when they
have been taken out of the body, it is because the surrounding medium,
and the substances with which it is charged, contribute to produce this
effect; they are then the stimuli of these organs.
In general the artificial stimuli act in different ways; 1st, by their
simple contact; 2d, by tearing or cutting mechanically the fibres; 3d,
by tending to combine with them; 4th, there are some of whose mode of
action we are completely ignorant; such for example is electricity.
When the stimuli act only by simple contact, the fluids are, all things
being equal, more efficacious than the solids, because they stimulate
by a greater number of points; as they irritate not only the surfaces
of the organ, but penetrate also into the interstices of the fibres.
The solids produce an effect in proportion to the extent of their
excitement, to the greater or less pressure that they exert, to their
density, their softness, &c. They are almost always fluid substances
that nature employs for stimuli in the ordinary state.
Tearing is a mode of excitement more active than contact. The heart,
the intestines often inert when they are only touched by the scalpel,
contract powerfully when the point of it excites them. Cutting produces
a less sensible effect than tearing. Cut transversely, the fibres
oscillate and are agitated only by the sensible organic contractility,
whilst by the contractility of texture they experience an evident
retraction.
Chemical excitement is, in the greatest number of cases, the most
advantageous; but it is necessary here to distinguish that which
belongs to the horny hardening, from that which is the effect of
irritability brought into action. 1st. Plunge a frog without skin and
alive into a concentrated acid; instantly every thing is disorganized;
the reagent acts so strongly, that we can distinguish neither horny
hardening nor contractility. 2d. Weaken the acid a little and plunge
into it, the inferior extremities only of a frog; in an instant they
stiffen by the contraction of the extensors, which overcome the
flexors; for in this experiment, this is almost a constant phenomenon;
withdraw the animal; its thighs remain immoveable, life has been
extinguished in them; the contraction that has come on is a horny
hardening, and not a vital phenomenon. A dead frog plunged into the
same liquor experiences the same phenomenon. 3d. Weaken the acid still
more; the instant the animal is plunged into it its limbs contract; but
relaxation succeeds the contractions; these are alternate motions; it
is the irritability that begins to be put into action. Yet if the acid
is not very weak, some marks of the horny hardening still remain, and
the animal has a stiffness in the motions of the inferior extremities,
the evident result of the first degree of this horny hardening. 4th.
Finally, if the acid is very weak, it becomes a simple irritant which
puts in action the sensible organic contractility, without altering
the texture of the fibres; the animal after coming out of the fluid
preserves the same power of motion.
These experiments which it would be easy to multiply upon animals with
warm blood, but which I have never attempted upon them, evidently show
what belongs to the horny hardening, and what is the effect of vital
contraction. Yet there is not an exact limit between them, and there is
one degree of weakness of the acid in which these two causes of motions
are confounded.
There is a mode of excitement to which authors have not paid attention;
it may be called negative; it is that of which I spoke just now on the
subject of caloric, the privation of which is oftentimes a very active
stimulant. In the different experiments that I have had occasion to
make, this has frequently struck me. Apply a stimulant to a muscle, it
contracts; but at the end of some time the motion ceases, though the
contact continues; remove the stimulant, the motion frequently returns
in an instant. In general, nothing is more common in the heart, the
intestines, &c. than their contractions ceasing under the continued
action of a stimulant, and returning instantly upon its absence. I
confess that this phenomenon is not as invariable and constant as that
of the contraction produced by the application of the stimulus which
succeeds a state of non-excitement; but this happens very often. We
might say that the organic sensibility is in this case like the animal,
that every new state affects it, whether it be positive or negative.
The passage from non-excitement to excitement is more lively; but the
opposite passage is not less when it is sudden. Moreover this manner
of describing the sensible organic contractility in exercise, deserves
some further experiments.
_Of the Sensible Organic Contractility considered in relation to the
Organs._
The sensible organic contractility, considered in the organ in which it
has its seat, exhibits numerous varieties which are relative; 1st, to
the diversity of texture; 2d, to age; 3d, to sex; 4th, to temperament,
&c.
_First Variety. Diversity of the Muscular Texture._
The animal contractility is everywhere the same in the voluntary
muscles, because their organization is uniform. All things being equal
as to the number and length of the fibres, the phenomena of contraction
are exactly the same everywhere; here, on the contrary, the varieties
of texture inevitably produce varieties in the vital properties.
Each involuntary muscle is at first especially in relation with
the fluid which ordinarily acts as its stimulus. The blood alone
can regularly support the motions of the heart. Let this fluid be
altered in any manner, the contractions become irregular. All foreign
substances forced into the veins produce this phenomenon. The urine,
which supports with harmony the motions of the bladder, would disturb
those of the heart, if it circulated in its cavities. The blood,
more soft in appearance than the urine, can agitate convulsively the
bladder, if it happens to be in it. I took care with Desault of a
patient affected for a long time with retention of urine, and whom
he had cut for a very large stone. After the operation, the urine
remained stagnant in the bladder as long as it was alone, but when a
little blood entered this organ, it contracted involuntarily and the
bloody urine was evacuated. The excrements, which could continue for
a long time in the rectum without making it contract, would make the
stomach heave in an instant, &c. All these phenomena are to be referred
to varieties of sensibility of the mucous membranes, varieties which we
shall notice again. They prove evidently that each muscle has a degree
of organic contractility which is peculiar to it, and that this or that
fluid of the economy can exclusively, in a natural state, put it in
exercise in a regular manner.
Foreign fluids exhibit the same result; the emetic which makes
the stomach contract, is injected with impunity into the bladder;
purgatives do not produce vomiting, &c. This relation of foreign fluids
with the sensible organic contractility takes place, whether, as in
the preceding case, these fluids are applied to the mucous surfaces
corresponding to the muscles, or whether they come to the muscles by
the circulation, as the experiments have proved which were made in the
last age upon the introduction of medicinal substances into the veins;
experiments of which Haller has collected a great number of results.
We have seen in these experiments, the circulation present to all the
organs sometimes an emetic, and the stomach alone contracts; sometimes
a purgative, and the intestines only enter into action, &c. Taken
in by cutaneous absorption, medicinal substances occasion the same
phenomenon. Applied by friction, purgatives, emetics, &c. do not make
all the organic muscles contract, though the circulation presents them
to all, but only those with which their sensibility is in relation.
In the various affections of which they are the seat, we see the
organic muscles having each a peculiar mode of irritation answer to
each stimulus, and remaining deaf, if we may so say, to the voice of
the others.
_Second Variety. Age._
Age modifies wonderfully the sensible organic contractility. In
infancy it is very evident; the muscles answer with extreme ease to
the stimuli; the bladder retains the urine with difficulty; children
void it in sleep involuntarily; the heart contracts with a rapidity of
which the pulse is the measure; all the digestive phenomena are more
prompt; hence there is less interval between the returns of hunger. It
is a phenomenon analogous to that of the voluntary muscles, in which
the rapidity of the motions is found, in the first age, connected with
their small degree of force.
After infancy, the susceptibility of the muscles to answer to their
stimuli, is constantly diminishing; thus all the great phenomena of
organic life are continually becoming slower. The number of pulsations,
the duration of digestion, the longer continuance of the urine, &c. are
the thermometer of this slowness.
In old age the whole is weakened; the action of the organic muscles
gradually diminishes. Those of the bladder and rectum are the most
exposed to lose their contractile faculty; hence the retention of
urine, which is a frequent companion of old age; hence also the
accumulation of fecal matters above the anus, a disease almost as
common as the first at this age of life, though it has received less
attention from practitioners. Rich people and those accustomed to the
luxury of the table are especially subject to it. I have seen much of
it, as much even as of retention of urine, in the last year of the
practice of Desault. The intestines and the stomach languish more
slowly in their functions. It is the heart which resists the most;
it is the ultimum moriens, as it has been the first in exercise; the
duration of its pulsations measures exactly the duration of organic
life.
_Third Variety. Temperament._
Temperament modifies in a remarkable manner organic contractility. We
know that in some the pulsations are more frequent, the digestive and
urinary phenomena more rapid; that in others, every thing is marked by
more slowness in organic life; now these varieties have evidently their
primitive source in the varieties of the contractility of the heart,
the stomach, the intestines, &c. which have under this relation a great
influence in the difference of the temperaments. With respect to this
there are two essential observations to be made; 1st. The varieties
of force of the organic muscles do not always coincide with those of
the muscles of animal life. Thus we see an individual with feebly
developed exterior forms, with an evident weakness of the muscles of
the extremities, whilst the activity of digestion, of the urinary
evacuations, &c. announces the greatest energy in the sensible organic
contractility. I would remark with regard to this, that the heart is
more frequently in relation of force with the external muscles than the
stomach, the intestines and the bladder. A full pulse, well developed,
is usually found with an athletic constitution; whilst often this
constitution is united in the same subject to a feeble gastric system,
and especially the force of this gastric system is frequently connected
with external weakness. This fact, which the different temperaments
demonstrate to us in man, is evident in the series of animals. Those
who, like the carnivorous ones, have a very powerful animal muscular
system, have the parietes of the gastric cavities like membranes.
These parietes are strong in the herbivorous classes; they become very
conspicuous in the gallinaceous. In general, mastication over which the
animal contractility always presides, is in animals in an inverse ratio
of the force of trituration of the stomach, over which the sensible
organic contractility presides.
2d. The varieties of this property, relative to temperaments, exhibit
another phenomenon almost always foreign to the animal muscular
system. In fact in this the varieties are always general; we are
able by exercise to strengthen this or that muscular region; but the
differences of forces which are natural, always influence the whole
system. The arms and the legs, the thorax and the abdomen are uniformly
contractile in the different divisions of the muscles that belong
to them. On the contrary, it is rare to see this uniformity in the
involuntary muscles. One almost always predominates over the others;
sometimes it is the heart, sometimes the stomach and sometimes the
bladder. The gastric viscera even are frequently not all at the same
level as to force. The stomach is feeble when the intestines preserve
their ordinary action; and reciprocally the intestines too contractile
expel immediately fecal matters and thus produce a diarrhœa, though
the stomach may perform its functions well. This essential difference
in the two muscular systems arises from the circumstance that the
contractility of one depends upon a common centre, the brain; whilst
that of the other on the contrary has its principle insulated in each
organ in which it exists.
_Fourth Variety. Sex._
Women in general resemble children in the phenomena of sensible organic
contractility. The weakness of the motions coincides with their greater
rapidity in this sex, all whose internal muscles, like the external,
are more delicate and less strongly developed than in man. It might
be said that the contractile power of the womb has been formed at the
expense of the forces of all the other organs. In experiments, females
give results much less decided and always less durable than males. The
motions of the heart, the stomach, the intestines, &c. cease sooner;
these motions are less; it requires stronger stimuli to produce them,
&c.
_Fifth Variety. Season and Climate._
In winter and in cold climates, in which the cutaneous organ
contracted, and having as it were the horny hardness from the
impression of the surrounding air, has but a feeble action, all the
internal functions more active, require more energy in the forces that
preside over them; all the digestive, urinary and circulatory phenomena
are more evident. I do not know that there has yet been made any
comparative experiments upon irritability in the different seasons; but
I am persuaded that they would give different results.
_Sensible Organic Contractility considered in relation to the Action of
Stimuli upon the Organs._
We have just described separately the stimulant and the organ
stimulated; each being separate there is no effect upon the sensible
organic contractility; from their union alone results the exercise of
this property. What happens in this union? We know not. To wish to know
it, would be to wish to know how one body attracts another, how an acid
combines with an alkali, &c. In attraction, affinity and irritability,
we can only trace the phenomena to the action of bodies upon each
other. This action is the utmost limit of our researches.
But that which ought not to escape us here is, that in this last
property, the action is never immediate. There is always between
the stimulus and the organ something intermediate which receives
the irritation; this intermediate organ is a delicate membrane and
continuous with that of the arteries for the heart; it is a mucous
surface for the gastric viscera and the bladder. This intermediate
organ is more susceptible of receiving excitement than the muscle
itself. I have uniformly observed that by irritating the internal
surface of the heart, its contractions are greater, than by laying its
texture bare externally by removing its serous covering and afterwards
stimulating it. The same is true with regard to the organic muscles of
the abdomen.
Is there between the intermediate organ excited and the organ which
contracts, any nervous communications that transmit the impression?
I think not, the cellular texture is sufficient. In fact the serous
surfaces and the organic muscles have only this texture as a means
of union. The life of the first is in no way connected with that of
the others, since they often leave them as we shall see, and yet they
can transmit excitement to them. The pericardium and the peritoneum,
irritated in their portion corresponding with the organ that we wish
to move, produce a contraction in it. This fact is known to all those
who have made the least experiment; it is almost always in this way
that we stimulate the heart, the stomach, the intestines, the bladder,
&c. By carrying the stimulus over the serous surface but very lightly,
and so as not to communicate the motion to the fleshy fibres, we
obtain a result. Yet simple contact is not sufficient to transmit
the irritation; for example, by leaving the external layer of the
pericardium applied to the heart and afterwards irritating it, the
organ remains immoveable. If we separate the peritoneum from above the
bladder, so as to break all the cellular adhesions, and afterwards
reapply and stimulate it, the same immobility is observed.
When the intermediate organ that receives the excitement is diseased,
the contractility is uniformly altered. The same stimulus produces slow
or rapid contractions, according as the affection raises or diminishes
the sensibility of this intermediate organ. A slight inflammation of
the exterior of the bladder produces a kind of incontinence of urine;
that of the intestines occasions diarrhœa, &c. &c. On the contrary,
old catarrhs of the bladder, the affections in which weakness of the
mucous surface of this organ predominates, are the frequent causes of
retention.
I would observe that the existence of this intermediate organ is a
remarkable difference between the sensible organic contractility and
the insensible, for this organ does not exist in this last, in which
the same system receives the impression and reacts upon the body that
has produced it; for example, in the glandular, serous, cutaneous
systems, &c. the fluid which enters them for secretion or exhalation
produces in them the sensation, which is instantly followed by the
reaction. In the sensible contractility on the contrary, one system
feels and another is moved. This kind of mobility is less removed from
that of animal life, in which the organs of the senses and those of the
motion being wholly different, are very distant from each other.
_Sensible Organic Contractility considered in relation to its duration
after Death._
This duration is longer than that of the animal contractility. When the
spinal marrow is irritated, the external muscles remain immoveable,
whilst the internal ones are still in activity. There have been so many
examples related of this duration, Haller has multiplied experiments so
much upon this point, that there is no occasion for me to give proofs
here of a fact of which no one can any longer doubt. To this duration
are owing the evacuations of fecal matter and urine which often take
place an instant after death; the vomitings that are observed in some
subjects, if not in as evident a manner as during life, at least
sufficient to raise the aliments into the mouth of the dead body, which
is often completely filled with them, as I have frequently seen.
It is necessary, in relation to this duration, as in relation to that
of the animal contractility, to distinguish two species of death; 1st,
those that take place suddenly; 2d, those which are the consequence of
long disease.
In every sudden death, produced either by a violent lesion of the
brain, as in apoplexy, concussion, compression, effusion, &c. or by
an affection of the heart, as in syncope, a wound, or a ruptured
aneurism; or by a cessation of the action of the lungs, as in asphyxia
from deleterious gases, a vacuum, submersion, &c. the duration of
contractility is very evident; general death comes on first, then the
organs die partially; each vital force is afterwards successively
extinguished.
In every kind of death slowly produced, in all those especially which
are preceded by a disease of weakness, it is the partial death of
each organ that first takes place; each vital force is weakened and
extinguished, gradually, before the cessation of them as a whole, which
constitutes general death, comes on; when this death takes place, none
of the lives peculiar to each organ remains, whilst most of these lives
continue for a longer or shorter time after sudden death.
We cannot make these experiments upon dead bodies which we rarely have
in the hospitals till fifteen hours or more after death; but by killing
dogs by hunger, which, when long continued, becomes a real disease
that lasts in these animals eight, ten and even twelve days, I have
seen the contractility entirely extinguished at the moment of death.
Dogs have been often brought to me affected with different diseases,
especially three years since when there was a kind of epidemic among
these animals; now by opening them at the instant of death, by killing
them even some time before and thus producing a sudden death wholly
different from that which happens in the sound state in which all the
parts are uninjured in their functions and consequently in their vital
forces, I have always seen a constant absence of contractility, or at
least so greatly weakened that it appeared to be nothing.
Many physiologists have spoken of a general convulsion which comes
on in the organic muscles at the instant of death, of a rising of
the heart, the stomach, the intestines, &c. This excess of action is
sometimes real in sudden deaths, in those especially that we produce
for our experiments; it is very rare in deaths preceded by a long
disease in which the patient is extinguished, as it were, insensibly,
and passes gradually from life to death. It is a fault common to almost
all authors, to generalize too much the facts observed under certain
circumstances. Many false consequences are the results of it.
_Sympathies._
No organ receives more easily the influence of others, than the organic
muscles; all however are not equally susceptible of it. The heart
occupies the first rank in this respect; then comes the stomach, then
the intestines, and finally the bladder. It is in this order that we
shall now examine this influence.