It may be adduced, that as the matter inserted into the skin of the arm frequently swells the lymphatic in the axilla, that in that circ.u.mstance it seems to be there arrested in its progress, and cannot be imagined to enter the blood by that lymphatic gland till the swelling of it subsides. Some other phaenomena of the disease are more easily reconcileable to this theory of sympathetic motions than to that of absorption; as the time taken up between the insertion of the matter, and the operation of it on the system, as mentioned above. For the circle around the insertion is seen to increase, and to inflame; and I believe, undergoes a kind of diurnal paroxysm of torpor and paleness with a succeeding increase of action and colour, like a topical fever-fit. Whereas if the matter is conceived to circulate for six or seven days with the blood, without producing disorder, it ought to be rendered milder, or the blood-vessels more familiarized to its acrimony.

It is much easier to conceive from this doctrine of a.s.sociated or sympathetic motions of distant parts of the system, how it happens, that the variolous infection can be received but once, as before explained; than by supposing, that a change is effected in the ma.s.s of blood by any kind of fermentative process.

The curious circ.u.mstance of the two contagions of small-pox and measles not acting at the same time, but one of them resting or suspending its action till that of the other ceases, may be much easier explained from sympathetic or a.s.sociated actions of the infected part with other parts of the system, than it can from supposing the two contagions to enter the circulation.

The skin of the face is subject to more frequent vicissitudes of heat and cold, from its exposure to the open air, and is in consequence more liable to sensitive a.s.sociation with the stomach than any other part of the surface of the body, because their actions have been more frequently thus a.s.sociated. Thus in a surfeit from drinking cold water, when a person is very hot and fatigued, an eruption is liable to appear on the face in consequence of this sympathy. In the same manner the rosy eruption on the faces of drunkards more probably arises from the sympathy of the face with the stomach, rather than between the face and the liver, as is generally supposed.

This sympathy between the stomach and the skin of the face is apparent in the eruption of the small-pox; since, where the disease is in considerable quant.i.ty, the eruption on the face first succeeds the sickness of the stomach. In the natural disease the stomach seems to be frequently primarily affected, either alone or along with the tonsils, as the matter seems to be only diffused in the air, and by being mixed with the saliva, or mucus of the tonsils, to be swallowed into the stomach.

After some days the irritative circles of motions become disordered by this new stimulus, which acts upon the mucus lining of the stomach; and sickness, vertigo, and a diurnal fever succeed. These disordered irritative motions become daily increased for two or three days, and then by their increased action certain sensitive motions, or inflammation, is produced, and at the next cold fit of fever, when the stomach recovers from its torpor, an inflammation of the external skin is formed in points (which afterwards suppurate), by sensitive a.s.sociation, in the same manner as a cough is produced in consequence of exposing the feet to cold, as described in Sect. XXV. 17. and Cla.s.s IV. 2. I. 7. If the inoculated skin of the arm, as far as it appears inflamed, was to be cut out, or destroyed by caustic, before the fever commenced, as suppose on the fourth day after inoculation, would this prevent the disease? as it is supposed to prevent the hydrophobia.

III. 1. Where the new vessels, and enlarged old ones, which const.i.tute inflammation, are not so hastily distended as to burst, and form a new kind of gland for the secretion of matter, as above mentioned; if such circ.u.mstances happen as diminish the painful sensation, the tendency to growth ceases, and by and by an absorption commences, not only of the superabundant quant.i.ty of fluids deposited in the inflamed part, but of the solids likewise, and this even of the hardest kind.

Thus during the growth of the second set of teeth in children, the roots of the first set are totally absorbed, till at length nothing of them remains but the crown; though a few weeks before, if they are drawn immaturely, their roots are found complete. Similar to this Mr. Hunter has observed, that where a dead piece of bone is to exfoliate, or to separate from a living one, that the dead part does not putrify, but remains perfectly sound, while the surface of the living part of the bone, which is in contact with the dead part, becomes absorbed, and thus effects its separation. Med. Comment. Edinb. V. 1. 425. In the same manner the calcareous matter of gouty concretions, the coagulable lymph deposited on inflamed membranes in rheumatism and extravasated blood become absorbed; which are all as solid and as indissoluble materials as the new vessels produced in inflammation.

This absorption of the new vessels and deposited fluids of inflamed parts is called resolution: it is produced by first using such internal means as decrease the pain of the part, and in consequence its new motions, as repeated bleeding, cathartics, diluent potations, and warm bath.

After the vessels are thus emptied, and the absorption of the new vessels and deposited fluids is evidently begun, it is much promoted by stimulating the part externally by solutions of lead, or other metals, and internally by the bark, and small doses of opium. Hence when an ophthalmy begins to become paler, any acrid eye-water, as a solution of six grains of white vitriol in an ounce of water, hastens the absorption, and clears the eye in a very short time. But the same application used a few days sooner would have increased the inflammation. Hence after evacuation opium in small doses may contribute to promote the absorption of fluids deposited on the brain, as observed by Mr. Bromfield in his treatise of surgery.

2. Where an abscess is formed by the rupture of these new vessels, the violence of inflammation ceases, and a new gland separates a material called pus: at the same time a less degree of inflammation produces new vessels called vulgarly proud flesh; which, if no bandage confines its growth, nor any other circ.u.mstance promotes absorption in the wound, would rise to a great height above the usual size of the part.

Hence the art of healing ulcers consists in producing a tendency to absorption in the wound greater than the deposition. Thus when an ill-conditioned ulcer separates a copious and thin discharge, by the use of any stimulus, as of salts of lead, or mercury, or copper externally applied, the discharge becomes diminished in quant.i.ty, and becomes thicker, as the thinner parts are first absorbed.

But nothing so much contributes to increase the absorption in a wound as covering the whole limb above the sore with a bandage, which should be spread with some plaster, as with emplastrum de minio, to prevent it from slipping. By this artificial tightness of the skin, the arterial pulsations act with double their usual power in promoting the ascending current of the fluid in the valvular lymphatics.

Internally the absorption from ulcers should be promoted first by evacuation, then by opium, bark, mercury, steel.

3. Where the inflammation proceeds with greater violence or rapidity, that is, when by the painful sensation a more inordinate activity of the organ is produced, and by this great activity an additional quant.i.ty of painful sensation follows in an increasing ratio, till the whole of the sensorial power, or spirit of animation, in the part becomes exhausted, a mortification ensues, as in a carbuncle, in inflammations of the bowels, in the extremities of old people, or in the limbs of those who are brought near a fire after having been much benumbed with cold. And from hence it appears, why weak people are more subject to mortification than strong ones, and why in weak persons less pain will produce mortification, namely, because the sensorial power is sooner exhausted by any excess of activity.

I remember seeing a gentleman who had the preceding day travelled two stages in a chaise with what he termed a bearable pain in his bowels; which when I saw him had ceased rather suddenly, and without a pa.s.sage through him; his pulse was then weak, though not very quick; but as nothing which he swallowed would continue in his stomach many minutes, I concluded that the bowel was mortified; he died on the next day. It is usual for patients sinking under the small-pox with mortified pustules, and with purple spots intermixed, to complain of no pain, but to say they are pretty well to the last moment.

_Recapitulation._

IV. When the motions of any part of the system, in consequence of previous torpor, are performed with more energy than in the irritative fevers, a disagreeable sensation is produced, and new actions of some part of the system commence in consequence of this sensation conjointly with the irritation: which motions const.i.tute inflammation. If the fever be attended with a strong pulse, as in pleurisy, or rheumatism, it is termed synocha sensitiva, or sensitive fever with strong pulse; which is usually termed inflammatory fever. If it be attended with weak pulse, it is termed typhus sensitivus, or sensitive fever with weak pulse, or typhus gravior, or putrid malignant fever.

The synocha sensitiva, or sensitive fever with strong pulse, is generally attended with some topical inflammation, as in peripneumony, hepat.i.tis, and is accompanied with much coagulable lymph, or size; which rises to the surface of the blood, when taken into a bason, as it cools; and which is believed to be the increased mucous secretion from the coats of the arteries, insp.i.s.sated by a greater absorption of its aqueous and saline part, and perhaps changed by its delay in the circulation.

The typhus sensitivus, or sensitive fever with weak pulse, is frequently attended with delirium, which is caused by the deficiency of the quant.i.ty of sensorial power, and with variety of cutaneous eruptions.

Inflammation is caused by the pains occasioned by excess of action, and not by those pains which are occasioned by defect of action. These morbid actions, which are thus produced by two sensorial powers, viz. by irritation and sensation, secrete new living fibres, which elongate the old vessels, or form new ones, and at the same time much heat is evolved from these combinations. By the rupture of these vessels, or by a new construction of their apertures, purulent matters are secreted of various kinds; which are infectious the first time they are applied to the skin beneath the cuticle, or swallowed with the saliva into the stomach. This contagion acts not by its being absorbed into the circulation, but by the sympathies, or a.s.sociated actions, between the part first stimulated by the contagious matter and the other parts of the system. Thus in the natural small-pox the contagion is swallowed with the saliva, and by its stimulus inflames the stomach; this variolous inflammation of the stomach increases every day, like the circle round the puncture of an inoculated arm, till it becomes great enough to disorder the circles of irritative and sensitive motions, and thus produces fever-fits, with sickness and vomiting. Lastly, after the cold paroxysm, or fit of torpor, of the stomach has increased for two or three successive days, an inflammation of the skin commences in points; which generally first appear upon the face, as the a.s.sociated actions between the skin of the face and that of the stomach have been more frequently exerted together than those of any other parts of the external surface.

Contagious matters, as those of the measles and small-pox, do not act upon the system at the same time; but the progress of that which was last received is delayed, till the action of the former infection ceases. All kinds of matter, even that from common ulcers, are probably contagious the first time they are inserted beneath the cuticle or swallowed into the stomach; that is, as they were formed by certain morbid actions of the extremities of the vessels, they have the power to excite similar morbid actions in the extremities of other vessels, to which they are applied; and these by sympathy, or a.s.sociations of motion, excite similar morbid actions in distant parts of the system, without entering the circulation; and hence the blood of a patient in the small-pox will not give that disease by inoculation to others.

When the new fibres or vessels become again absorbed into the circulation, the inflammation ceases; which is promoted, after sufficient evacuations, by external stimulants and bandages: but where the action of the vessels is very great, a mortification of the part is liable to ensue, owing to the exhaustion of sensorial power; which however occurs in weak people without much pain, and without very violent previous inflammation; and, like partial paralysis, may be esteemed one mode of natural death of old people, a part dying before the whole.

SECT. x.x.xIV.

DISEASES OF VOLITION.

I. 1. _Volition defined. Motions termed involuntary are caused by volition. Desires opposed to each other. Deliberation. a.s.s between two hay-c.o.c.ks. Saliva swallowed against one's desire. Voluntary motions distinguished from those a.s.sociated with sensitive motions._ 2. _Pains from excess, and from defect of motion. No pain is felt during vehement voluntary exertion; as in cold fits of ague, labour-pains, strangury, tenesmus, vomiting, restlessness in fevers, convulsion of a wounded muscle._ 3. _Of holding the breath and screaming in pain; why swine and dogs cry out in pain, and not sheep and horses. Of grinning and biting in pain; why mad animals bite others._ 4. _Epileptic convulsions explained, why the fits begin with quivering of the under jaw, biting the tongue, and setting the teeth; why the convulsive motions are alternately relaxed. The phenomenon of laughter explained. Why children cannot tickle themselves. How some have died from immoderate laughter._ 5. _Of cataleptic spasms, of the locked jaw, of painful cramps._ 6.

_Syncope explained. Why no external objects are perceived in syncope._ 7. _Of palsy and apoplexy from violent exertions. Case of Mrs. Scot.

From dancing, scating, swimming. Case of Mr. Nairn. Why palsies are not always immediately preceded by violent exertions. Palsy and epilepsy from diseased livers. Why the right arm more frequently paralytic than the left. How paralytic limbs regain their motions._ II. _Diseases of the sensual motions from excess or defect of voluntary exertion._ 1.

_Madness._ 2. _Distinguished from delirium._ 3. _Why mankind more liable to insanity than brutes._ 4. _Suspicion. Want of shame, and of cleanliness._ 5. _They bear cold, hunger, and fatigue. Charles XII. of Sweden._ 6. _Pleasureable delirium, and insanity. Child riding on a stick. Pains of martyrdom not felt._ 7. _Dropsy._ 8. _Inflammation cured by insanity._ III. 1. _Pain relieved by reverie. Reverie is an exertion of voluntary and sensitive motions._ 2. _Case of reverie._ 3.

_Lady supposed to have two souls._ 4. _Methods of relieving pain._

I. 1. Before we commence this Section on Diseased Voluntary Motions, it may be necessary to premise, that the word volition is not used in this work exactly in its common acceptation. Volition is said in Section V. to bear the same a.n.a.logy to desire and aversion, which sensation does to pleasure and pain. And hence that, when desire or aversion produces any action of the muscular fibres, or of the organs of sense, they are termed volition; and the actions produced in consequence are termed voluntary actions.

Whence it appears, that motions of our muscles or ideas may be produced in consequence of desire or aversion without our having the power to prevent them, and yet these motions may be termed voluntary, according to our definition of the word; though in common language they would be called involuntary.

The objects of desire and aversion are generally at a distance, whereas those of pleasure and pain are immediately acting upon our organs. Hence, before desire or aversion are exerted, so as to cause any actions, there is generally time for deliberation; which consists in discovering the means to obtain the object of desire, or to avoid the object of aversion; or in examining the good or bad consequences, which may result from them. In this case it is evident, that we have a power to delay the proposed action, or to perform it; and this power of choosing, whether we shall act or not, is in common language expressed by the word volition, or will. Whereas in this work the word volition means simply the active state of the sensorial faculty in producing motion in consequence of desire or aversion: whether we have the power of restraining that action, or not; that is, whether we exert any actions in consequence of opposite desires or aversions, or not.

For if the objects of desire or aversion are present, there is no necessity to investigate or compare the _means_ of obtaining them, nor do we always deliberate about their consequences; that is, no deliberation necessarily intervenes, and in consequence the power of choosing to act or not is not exerted. It is probable, that this twofold use of the word volition in all languages has confounded the metaphysicians, who have disputed about free will and necessity. Whereas from the above a.n.a.lysis it would appear, that during our sleep, we use no voluntary exertions at all; and in our waking hours, that they are the consequence of desire or aversion.

To will is to act in consequence of desire; but to desire means to desire something, even if that something be only to become free from the pain, which causes the desire; for to desire nothing is not to desire; the word desire, therefore, includes both the action and the object or motive; for the object and motive of desire are the same thing. Hence to desire without an object, that is, without a motive, is a solecism in language. As if one should ask, if you could eat without food, or breathe without air.

From this account of volition it appears, that convulsions of the muscles, as in epileptic fits, may in the common sense of that word be termed involuntary; because no deliberation is interposed between the desire or aversion and the consequent action; but in the sense of the word, as above defined, they belong to the cla.s.s of voluntary motions, as delivered in Vol. II. Cla.s.s III. If this use of the word be discordant to the ear of the reader, the term morbid voluntary motions, or motions in consequence of aversion, may be subst.i.tuted in its stead.

If a person has a desire to be cured of the ague, and has at the same time an aversion (or contrary desire) to swallowing an ounce of Peruvian bark; he balances desire against desire, or aversion against aversion; and thus he acquires the power of choosing, which is the common acceptation of the word _willing_. But in the cold fit of ague, after having discovered that the act of shuddering, or exerting the subcutaneous muscles, relieves the pain of cold; he immediately exerts this act of volition, and shudders, as soon as the pain and consequent aversion return, without any deliberation intervening; yet is this act, as well as that of swallowing an ounce of the bark, caused by volition; and that even though he endeavours in vain to prevent it by a weaker contrary volition. This recalls to our minds the story of the hungry a.s.s between two hay-stacks, where the two desires are supposed so exactly to counteract each other, that he goes to neither of the stacks, but perishes by want. Now as two equal and opposite desires are thus supposed to balance each other, and prevent all action, it follows, that if one of these hay-stacks was suddenly removed, that the a.s.s would irresistibly be hurried to the other, which in the common use of the word might be called an involuntary act; but which, in our acceptation of it, would be cla.s.sed amongst voluntary actions, as above explained.

Hence to deliberate is to compare opposing desires or aversions, and that which is the most interesting at length prevails, and produces action.

Similar to this, where two pains oppose each other, the stronger or more interesting one produces action; as in pleurisy the pain from suffocation would produce expansion of the lungs, but the pain occasioned by extending the inflamed membrane, which lines the chest, opposes this expansion, and one or the other alternately prevails.

When any one moves his hand quickly near another person's eyes, the eye-lids instantly close; this act in common language is termed involuntary, as we have not time to deliberate or to exert any contrary desire or aversion, but in this work it would be termed a voluntary act, because it is caused by the faculty of volition, and after a few trials the nict.i.tation can be prevented by a contrary or opposing volition.

The power of opposing volitions is best exemplified in the story of Mutius Scaevola, who is said to have thrust his hand into the fire before Porcenna, and to have suffered it to be consumed for having failed him in his attempt on the life of that general. Here the aversion for the loss of same, or the unsatisfied desire to serve his country, the two prevalent enthusiasms at that time, were more powerful than the desire of withdrawing his hand, which must be occasioned by the pain of combustion; of these opposing volitions

Vincit amor patriae, laudumque immensa cupido.

If any one is told not to swallow his saliva for a minute, he soon swallows it contrary to his will, in the common sense of that word; but this also is a voluntary action, as it is performed by the faculty of volition, and is thus to be understood. When the power of volition is exerted on any of our senses, they become more acute, as in our attempts to hear small noises in the night. As explained in Section XIX. 6. Hence by our attention to the fauces from our desire not to swallow our saliva; the fauces become more sensible; and the stimulus of the saliva is followed by greater sensation, and consequent desire of swallowing it. So that the desire or volition in consequence of the increased sensation of the saliva is more powerful, than the previous desire not to swallow it. See Vol. II. Deglut.i.tio invita. In the same manner if a modest man wishes not to want to make water, when he is confined with ladies in a coach or an a.s.sembly-room; that very act of volition induces the circ.u.mstance, which he wishes to avoid, as above explained; insomuch that I once saw a partial insanity, which might be called a voluntary diabetes, which was occasioned by the fear (and consequent aversion) of not being able to make water at all.

It is further necessary to observe here, to prevent any confusion of voluntary, with sensitive, or a.s.sociate motions, that in all the instances of violent efforts to relieve pain, those efforts are at first voluntary exertions; but after they have been frequently repeated for the purpose of relieving certain pains, they become a.s.sociated with those pains, and cease at those times to be subservient to the will; as in coughing, sneezing, and strangury. Of these motions those which contribute to remove or dislodge the offending cause, as the actions of the abdominal muscles in parturition or in vomiting, though they were originally excited by volition, are in this work termed sensitive motions; but those actions of the muscles or organs of sense, which do not contribute to remove the offending cause, as in general convulsions or in madness, are in this work termed voluntary motions, or motions in consequence of aversion, though in common language they are called involuntary ones. Those sensitive unrestrainable actions, which contribute to remove the cause of pain are uniformly and invariably exerted, as in coughing or sneezing; but those motions which are exerted in consequence of aversion without contributing to remove the painful cause, but only to prevent the sensation of it, as in epileptic, or cataleptic fits, are not uniformly and invariably exerted, but change from one set of muscles to another, as will be further explained; and may by this criterion also be distinguished from the former.

At the same time those motions, which are excited by perpetual stimulus, or by a.s.sociation with each other, or immediately by pleasureable or painful sensation, may properly be termed involuntary motions, as those of the heart and arteries; as the faculty of volition seldom affects those, except when it exists in unnatural quant.i.ty, as in maniacal people.

2. It was observed in Section XIV. on the Production of Ideas, that those parts of the system, which are usually termed the organs of sense, are liable to be excited into pain by the excess of the stimulus of those objects, which are by nature adapted to affect them; as of too great light, sound, or pressure. But that these organs receive no pain from the defect or absence of these stimuli, as in darkness or silence. But that our other organs of perception, which have generally been called appet.i.tes, as of hunger, thirst, want of heat, want of fresh air, are liable to be affected with pain by the defect, as well as by the excess of their appropriated stimuli.

This excess or defect of stimulus is however to be considered only as the remote cause of the pain, the immediate cause being the excess or defect of the natural action of the affected part, according to Sect. IV. 5. Hence all the pains of the body may be divided into those from excess of motion, and those from defect of motion; which distinction is of great importance in the knowledge and the cure of many diseases. For as the pains from excess of motion either gradually subside, or are in general succeeded by inflammation; so those from defect of motion either gradually subside, or are in general succeeded by convulsion, or madness. These pains are easily distinguishable from each other by this circ.u.mstance, that the former are attended with heat of the pained part, or of the whole body; whereas the latter exists without increase of heat in the pained part, and is generally attended with coldness of the extremities of the body; which is the true criterion of what have been called nervous pains.

Thus when any acrid material, as snuff or lime, falls into the eye, pain and inflammation and heat are produced from the excess of stimulus; but violent hunger, hemicrania, or the clavus hystericus, are attended with coldness of the extremities, and defect of circulation. When we are exposed to great cold, the pain we experience from the deficiency of heat is attended with a quiescence of the motions of the vascular system; so that no inflammation is produced, but a great desire of heat, and a tremulous motion of the subcutaneous muscles, which is properly a convulsion in consequence of this pain from defect of the stimulus of heat.

It was before mentioned, that as sensation consists in certain movements of the sensorium, beginning at some of the extremities of it, and propagated to the central parts of it; so volition consists of certain other movements of the sensorium, commencing in the central parts of it, and propagated to some of its extremities. This idea of these two great powers of motion in the animal machine is confirmed from observing, that they never exist in a great degree or universally at the same time; for while we strongly exert our voluntary motions, we cease to feel the pains or uneasinesses, which occasioned us to exert them.

Hence during the time of fighting with fists or swords no pain is felt by the combatants, till they cease to exert themselves. Thus in the beginning of ague-fits the painful sensation of cold is diminished, while the patient exerts himself in the shivering and gnashing of his teeth. He then ceases to exert himself, and the pain of cold returns; and he is thus perpetually induced to reiterate these exertions, from which he experiences a temporary relief. The same occurs in labour-pains, the exertion of the parturient woman relieves the violence of the pains for a time, which recur again soon after she has ceased to use those exertions. The same is true in many other painful diseases, as in the strangury, tenesmus, and the efforts of vomiting; all these disagreeable sensations are diminished or removed for a time by the various exertions they occasion, and recur alternately with those exertions.

The restlessness in some fevers is an almost perpetual exertion of this kind, excited to relieve some disagreeable sensations; the reciprocal opposite exertions of a wounded worm, the alternate emprosthotonos and opisthotonos of some spasmodic diseases, and the intervals of all convulsions, from whatever cause, seem to be owing to this circ.u.mstance of the laws of animation; that great or universal exertion cannot exist at the same time with great or universal sensation, though they can exist reciprocally; which is probably resolvable into the more general law, that the whole sensorial power being expended in one mode of exertion, there is none to spare for any other. Whence syncope, or temporary apoplexy, succeeds to epileptic convulsions.

3. Hence when any violent pain afflicts us, of which we can neither avoid nor remove the cause, we soon learn to endeavour to alleviate it, by exerting some violent voluntary effort, as mentioned above; and are naturally induced to use those muscles for this purpose, which have been in the early periods of our lives most frequently or most powerfully exerted.

Now the first muscles, which infants use most frequently, are those of respiration; and on this account we gain a habit of holding our breath, at the same time that we use great efforts to exclude it, for this purpose of alleviating unavoidable pain; or we press out our breath through a small aperture of the larynx, and scream violently, when the pain is greater than is relievable by the former mode of exertion. Thus children scream to relieve any pain either of body or mind, as from anger, or fear of being beaten.