IX. 1. We now step forwards to consider the other symptoms in consequence of the quiescence which begins the fits of fever. If by any of the circ.u.mstances before described, or by two or more of them acting at the same time, a great degree of quiescence is induced on any considerable part of the circle of irritative motions, the whole cla.s.s of them is more or less disturbed by their irritative a.s.sociations. If this torpor be occasioned by a deficient supply of sensorial power, and happens to any of those parts of the system, which are accustomed to perpetual activity, as the vital motions, the torpor increases rapidly, because of the great expenditure of sensorial power by the incessant activity of those parts of the system, as shewn in No. 3. 2. of this Section. Hence a deficiency of all the secretions succeeds, and as animal heat is produced in proportion to the quant.i.ty of those secretions, the coldness of the skin is the first circ.u.mstance, which is attended to. Dr. Martin a.s.serts, that some parts of his body were warmer than natural in the cold fit of fever; but it is certain, that those, which are uncovered, as the fingers, and nose, and ears, are much colder to the touch, and paler in appearance. It is possible, that his experiments were made at the beginning of the subsequent hot fits; which commence with partial distributions of heat, owing to some parts of the body regaining their natural irritability sooner than others.

From the quiescence of the anastomosing capillaries a paleness of the skin succeeds, and a less secretion of the perspirable matter; from the quiescence of the pulmonary capillaries a difficulty of respiration arises; and from the quiescence of the other glands less bile, less gastric and pancreatic juice, are secreted into the stomach and intestines, and less mucus and saliva are poured into the mouth; whence arises the dry tongue, costiveness, dry ulcers, and paucity of urine. From the quiescence of the absorbent system arises the great thirst, as less moisture is absorbed from the atmosphere. The absorption from the atmosphere was observed by Dr.

Lyster to amount to eighteen ounces in one night, above what he had at the same time insensibly perspired. See Langrish. On the same account the urine is pale, though in small quant.i.ty, for the thinner part is not absorbed from it; and when repeated ague-fits continue long, the legs swell from the diminished absorption of the cellular absorbents.

From the quiescence of the intestinal ca.n.a.l a loss of appet.i.te and flatulencies proceed. From the partial quiescence of the glandular viscera a swelling and tension about the praecordia becomes sensible to the touch; which is occasioned by the delay of the fluids from the defect of venous or lymphatic absorption. The pain of the forehead, and of the limbs, and of the small of the back, arises from the quiescence of the membranous fascia, or muscles of those parts, in the same manner as the skin becomes painful, when the vessels, of which it is composed, become quiescent from cold. The trembling in consequence of the pain of coldness, the restlessness, and the yawning, and stretching of the limbs, together with the shuddering, or rigours, are convulsive motions; and will be explained amongst the diseases of volition; Sect. x.x.xIV.

Sickness and vomiting is a frequent symptom in the beginnings of fever-fits, the muscular fibres of the stomach share the general torpor and debility of the system; their motions become first lessened, and then stop, and then become retrograde; for the act of vomiting, like the globus hystericus and the borborigmi of hypochondriasis, is always a symptom of debility, either from want of stimulus, as in hunger; or from want of sensorial power, as after intoxication; or from sympathy with some other torpid irritative motions, as in the cold fits of ague. See Sect. XII. 5.

5. XXIX. 11. and x.x.xV. 1. 3. where this act of vomiting is further explained.

The small pulse, which is said by some writers to be slow at the commencement of ague-fits, and which is frequently trembling and intermittent, is owing to the quiescence of the heart and arterial system, and to the resistance opposed to the circulating fluid from the inactivity of all the glands and capillaries. The great weakness and inability to voluntary motions, with the insensibility of the extremities, are owing to the general quiescence of the whole moving system; or, perhaps, simply to the deficient production of sensorial power.

If all these symptoms are further increased, the quiescence of all the muscles, including the heart and arteries, becomes complete, and death ensues. This is, most probably, the case of those who are starved to death with cold, and of those who are said to die in Holland from long skaiting on their frozen ca.n.a.ls.

2. As soon as this general quiescence of the system ceases, either by the diminution of the cause, or by the acc.u.mulation of sensorial power, (as in syncope, Sect. XII. 7. 1.) which is the natural consequence of previous quiescence, the hot fit commences. Every gland of the body is now stimulated into stronger action than is natural, as its irritability is increased by acc.u.mulation of sensorial power during its late quiescence, a superabundance of all the secretions is produced, and an increase of heat in consequence of the increase of these secretions. The skin becomes red, and the perspiration great, owing to the increased action of the capillaries during the hot part of the paroxysm. The secretion of perspirable matter is perhaps greater during the hot fit than in the sweating fit which follows; but as the absorption of it also is greater, it does not stand on the skin in visible drops: add to this, that the evaporation of it also is greater, from the increased heat of the skin. But at the decline of the hot fit, as the mouths of the absorbents of the skin are exposed to the cooler air, or bed-clothes, these vessels sooner lose their increased activity, and cease to absorb more than their natural quant.i.ty: but the secerning vessels for some time longer, being kept warm by the circulating blood, continue to pour out an increased quant.i.ty of perspirable matter, which now stands on the skin in large visible drops; the exhalation of it also being lessened by the greater coolness of the skin, as well as its absorption by the diminished action of the lymphatics.

See Cla.s.s I. 1. 2. 3.

The increased secretion of bile and of other fluids poured into the intestines frequently induce a purging at the decline of the hot fit; for as the external absorbent vessels have their mouths exposed to the cold air, as above mentioned, they cease to be excited into unnatural activity sooner than the secretory vessels, whose mouths are exposed to the warmth of the blood: now, as the internal absorbents sympathize with the external ones, these also, which during the hot fit drank up the thinner part of the bile, or of other secreted fluids, lose their increased activity before the gland loses its increased activity, at the decline of the hot fit; and the loose dejections are produced from the same cause, that the increased perspiration stands on the surface of the skin, from the increased absorption ceasing sooner than the increased secretion.

The urine during the cold fit is in small quant.i.ty and pale, both from a deficiency of the secretion and a deficiency of the absorption.

During the hot fit it is in its usual quant.i.ty, but very high coloured and turbid, because a greater quant.i.ty had been secreted by the increased action of the kidnies, and also a greater quant.i.ty of its more aqueous part had been absorbed from it in the bladder by the increased action of the absorbents; and lastly, at the decline of the hot fit it is in large quant.i.ty and less coloured, or turbid, because the absorbent vessels of the bladder, as observed above, lose their increased action by sympathy with the cutaneous ones sooner than the secretory vessels of the kidnies lose their increased activity. Hence the quant.i.ty of the sediment, and the colour of the urine, in fevers, depend much on the quant.i.ty secreted by the kidnies, and the quant.i.ty absorbed from it again in the bladder: the kinds of sediment, as the lateritious, purulent, mucous, or b.l.o.o.d.y sediments, depend on other causes. It should be observed, that if the sweating be increased by the heat of the room, or of the bed-clothes, that a paucity of turbid urine will continue to be produced, as the absorbents of the bladder will have their activity increased by their sympathy with the vessels of the skin, for the purpose of supplying the fluid expended in perspiration.

The pulse becomes strong and full owing to the increased irritability of the heart and arteries, from the acc.u.mulation of sensorial power during their quiescence, and to the quickness of the return of the blood from the various glands and capillaries. This increased action of all the secretory vessels does not occur very suddenly, nor universally at the same time. The heat seems to begin about the center, and to be diffused from thence irregularly to the other parts of the system. This may be owing to the situation of the parts which first became quiescent and caused the fever-fit, especially when a hardness or tumour about the praecordia can be felt by the hand; and hence this part, in whatever viscus it is seated, might be the first to regain its natural or increased irritability.

3. It must be here noted, that, by the increased quant.i.ty of heat, and of the impulse of the blood at the commencement of the hot fit, a great increase of stimulus is induced, and is now added to the increased irritability of the system, which was occasioned by its previous quiescence. This additional stimulus of heat and momentum of the blood augments the violence of the movements of the arterial and glandular system in an increasing ratio. These violent exertions still producing more heat and greater momentum of the moving fluids, till at length the sensoral power becomes wasted by this great stimulus beneath its natural quant.i.ty, and predisposes the system to a second cold fit.

At length all these unnatural exertions spontaneously subside with the increased irritability that produced them; and which was itself produced by the preceding quiescence, in the same manner as the eye, on coming from darkness into day-light, in a little time ceases to be dazzled and pained, and gradually recovers its natural degree of irritability.

4. But if the increase of irritability, and the consequent increase of the stimulus of heat and momentum, produce more violent exertions than those above described; great pain arises in some part of the moving system, as in the membranes of the brain, pleura, or joints; and new motions of the vessels are produced in consequence of this pain, which are called inflammation; or delirium or stupor arises; as explained in Sect. XXI. and x.x.xIII.: for the immediate effect is the same, whether the great energy of the moving organs arises from an increase of stimulus or an increase of irritability; though in the former case the waste of sensorial power leads to debility, and in the latter to health.

_Recapitulation._

X. Those muscles, which are less frequently exerted, and whose actions are interrupted by sleep, acquire less acc.u.mulation of sensorial power during their quiescent state, as the muscles of locomotion. In these muscles after great exertion, that is, after great exhaustion of sensorial power, the pain of fatigue ensues; and during rest there is a renovation of the natural quant.i.ty of sensorial power; but where the rest, or quiescence of the muscle, is long continued, a quant.i.ty of sensorial power becomes acc.u.mulated beyond what is necessary; as appears by the uneasiness occasioned by want of exercise; and which in young animals is one cause exciting them into action, as is seen in the play of puppies and kittens.

But when those muscles, which are habituated to perpetual actions, as those of the stomach by the stimulus of food, those of the vessels of the skin by the stimulus of heat, and those which const.i.tute the arteries and glands by the stimulus of the blood, become for a time quiescent, from the want of their appropriated stimuli, or by their a.s.sociations with other quiescent parts of the system; a greater acc.u.mulation of sensorial power is acquired during their quiescence, and a greater or quicker exhaustion of it is produced during their increased action.

This acc.u.mulation of sensorial power from deficient action, if it happens to the stomach from want of food, occasions the pain of hunger; if it happens to the vessels of the skin from want of heat, it occasions the pain of cold; and if to the arterial system from the want of its adapted stimuli, many disagreeable sensations are occasioned, such as are experienced in the cold fits of intermittent fevers, and are as various, as there are glands or membranes in the system, and are generally termed universal uneasiness.

When the quiescence of the arterial system is not owing to defect of stimulus as above, but to the defective quant.i.ty of sensorial power, as in the commencement of nervous fever, or irritative fever with weak pulse, a great torpor of this system is quickly induced; because both the irritation from the stimulus of the blood, and the a.s.sociation of the vascular motions with each other, continue to excite the arteries into action, and thence quickly exhaust the ill-supplied vascular muscles; for to rest is death; and therefore those vascular muscles continue to proceed, though with feebler action, to the extreme of weariness or faintness: while nothing similar to this affects the locomotive muscles, whose actions are generally caused by volition, and not much subject either to irritation or to other kinds of a.s.sociations besides the voluntary ones, except indeed when they are excited by the lash of slavery.

In these vascular muscles, which are subject to perpetual action, and thence liable to great acc.u.mulation of sensorial power during their quiescence from want of stimulus, a great increase of activity occurs, either from the renewal of their accustomed stimulus, or even from much less quant.i.ties of stimulus than usual. This increase of action const.i.tutes the hot fit of fever, which is attended with various increased secretions, with great concomitant heat, and general uneasiness. The uneasiness attending this hot paroxysm of fever, or fit of exertion, is very different from that, which attends the previous cold fit, or fit of quiescence, and is frequently the cause of inflammation, as in pleurisy, which is treated of in the next section.

A similar effect occurs after the quiescence of our organs of sense; those which are not subject to perpetual action, as the taste and smell, are less liable to an exuberant acc.u.mulation of sensorial power after their having for a time been inactive; but the eye, which is in perpetual action during the day, becomes dazzled, and liable to inflammation after a temporary quiescence.

Where the previous quiescence has been owing to a defect of sensorial power, and not to a defect of stimulus, as in the irritative fever with weak pulse, a similar increase of activity of the arterial system succeeds, either from the usual stimulus of the blood, or from a stimulus less than usual; but as there is in general in these cases of fever with weak pulse a deficiency of the quant.i.ty of the blood, the pulse in the hot fit is weaker than in health, though it is stronger than in the cold fit, as explained in No. 2. of this section. But at the same time in those fevers, where the defect of irritation is owing to the defect of the quant.i.ty of sensorial power, as well as to the defect of stimulus, another circ.u.mstance occurs; which consists in the partial distribution of it, as appears in partial flushings, as of the face or bosom, while the extremities are cold; and in the increase of particular secretions, as of bile, saliva, insensible perspiration, with great heat of the skin, or with partial sweats, or diarrhoea.

There are also many uneasy sensations attending these increased actions, which, like those belonging to the hot fit of fever with strong pulse, are frequently followed by inflammation, as in scarlet fever; which inflammation is nevertheless accompanied with a pulse weaker, though quicker, than the pulse during the remission or intermission of the paroxysms, though stronger than that of the previous cold fit.

From hence I conclude, that both the cold and hot fits of fever are necessary consequences of the perpetual and incessant action of the arterial and glandular system; since those muscular fibres and those organs of sense, which are most frequently exerted, become necessarily most affected both with defect and acc.u.mulation of sensorial power: and that hence _fever-fits are not an effort of nature to relieve herself_, and that therefore they should always be prevented or diminished as much as possible, by any means which decrease the general or partial vascular actions, when they are greater, or by increasing them when they are less than in health, as described in Sect. XII. 6. 1.

Thus have I endeavoured to explain, and I hope to the satisfaction of the candid and patient reader, the princ.i.p.al symptoms or circ.u.mstances of fever without the introduction of the supernatural power of spasm. To the arguments in favour of the doctrine of spasm it may be sufficient to reply, that in the evolution of medical as well as of dramatic catastrophe,

Nec Deus intersit, nisi dignus vindice nodus inciderit.--HOR.

SECT. x.x.xIII.

DISEASES OF SENSATION.

I. 1. _Motions excited by sensation. Digestion. Generation. Pleasure of existence. Hypochondriacism._ 2. _Pain introduced. Sensitive fevers of two kinds._ 3. _Two sensorial powers exerted in sensitive fevers. Size of the blood. Nervous fevers distinguished from putrid ones. The septic and antiseptic theory._ 4. _Two kinds of delirium._ 5. _Other animals are less liable to delirium, cannot receive our contagious diseases, and are less liable to madness._ II. 1. _Sensitive motions generated._ 2. _Inflammation explained._ 3. _Its remote causes from excess of irritation, or of irritability, not from those pains which are owing to defect of irritation. New vessels produced, and much heat._ 4.

_Purulent matter secreted._ 5. _Contagion explained._ 6. _Received but once._ 7. _If common matter be contagious?_ 8. _Why some contagions are received but once._ 9. _Why others may be received frequently.

Contagions of small-pox and measles do not act at the same times. Two cases of such patients._ 10. _The blood from patients in the small-pox will not infect others. Cases of children thus inoculated. The variolous contagion is not received into the blood. It acts by sensitive a.s.sociation between the stomach and skin._ III. 1.

_Absorption of solids and fluids._ 2. _Art of healing ulcers._ 3.

_Mortification attended with less pain in weak people._

I. 1. As many motions of the body are excited and continued by irritations, so others require, either conjunctly with these, or separately, the pleasurable or painful sensations, for the purpose of producing them with due energy. Amongst these the business of digestion supplies us with an instance: if the food, which we swallow, is not attended with agreeable sensation, it digests less perfectly; and if very disagreeable sensation accompanies it, such as a nauseous idea, or very disgustful taste, the digestion becomes impeded; or retrograde motions of the stomach and oesophagus succeed, and the food is ejected.

The business of generation depends so much on agreeable sensation, that, where the object is disgustful, neither voluntary exertion nor irritation can effect the purpose; which is also liable to be interrupted by the pain of fear or bashfulness.

Besides the pleasure, which attends the irritations produced by the objects of l.u.s.t and hunger, there seems to be a sum of pleasurable affection accompanying the various secretions of the numerous glands, which const.i.tute the pleasure of life, in contradistinction to the tedium vitae.

This quant.i.ty or sum of pleasurable affection, seems to contribute to the due or energetic performance of the whole moveable system, as well that of the heart and arteries, as of digestion and of absorption; since without the due quant.i.ty of pleasurable sensation, flatulency and hypochondriacism affect the intestines, and a languor seizes the arterial pulsations and secretions; as occurs in great and continued anxiety of the mind.

2. Besides the febrile motions occasioned by irritation, described in Sect.

x.x.xII. and termed irritative fever, it frequently happens that pain is excited by the violence of the fibrous contractions; and other new motions are then superadded, in consequence of sensation, which we shall term febris sensitiva, or sensitive fever. It must be observed, that most irritative fevers begin with a decreased exertion of irritation, owing to defect of stimulus; but that on the contrary the sensitive fevers, or inflammations, generally begin with the increased exertion of sensation, as mentioned in Sect. x.x.xI. on temperaments: for though the cold fit, which introduces inflammation, commences with decreased irritation, yet the inflammation itself commences in the hot fit during the increase of sensation. Thus a common pustule, or phlegmon, in a part of little sensibility does not excite an inflammatory fever; but if the stomach, intestines, or the tender substance beneath the nails, be injured, great sensation is produced, and the whole system is thrown into that kind of exertion, which const.i.tutes inflammation.

These sensitive fevers, like the irritative ones, resolve themselves into those with arterial strength, and those with arterial debility, that is with excess or defect of sensorial power; these may be termed the febris sensitiva pulsu forti, sensitive fever with strong pulse, which is the synocha, or inflammatory fever; and the febris sensitiva pulsu debili, sensitive fever with weak pulse, which is the typhus gravior, or putrid fever of some writers.

3. The inflammatory fevers, which are here termed sensitive fevers with strong pulse, are generally attended with some topical inflammation, as pleurisy, peripneumony, or rheumatism, which distinguishes them from irritative fevers with strong pulse. The pulse is strong, quick, and full; for in this fever there is great irritation, as well as great sensation, employed in moving the arterial system. The size, or coagulable lymph, which appears on the blood, is probably an increased secretion from the inflamed internal lining of the whole arterial system, the thinner part being taken away by the increased absorption of the inflamed lymphatics.

The sensitive fevers with weak pulse, which are termed putrid or malignant fevers, are distinguished from irritative fevers with weak pulse, called nervous fevers, described in the last section, as the former consist of inflammation joined with debility, and the latter of debility alone. Hence there is greater heat and more florid colour of the skin in the former, with petechiae, or purple spots, and aphthae, or sloughs in the throat, and generally with previous contagion.

When animal matter dies, as a slough in the throat, or the mortified part of a carbuncle, if it be kept moist and warm, as during its abhesion to a living body, it will soon putrify. This, and the origin of contagion from putrid animal substances, seem to have given rise to the septic and antiseptic theory of these fevers.

The matter in pustules and ulcers is thus liable to become putrid, and to produce microscopic animalcula; the urine, if too long retained, may also gain a putrescent smell, as well as the alvine feces; but some writers have gone so far as to believe, that the blood itself in these fevers has smelt putrid, when drawn from the arm of the patient: but this seems not well founded; since a single particle of putrid matter taken into the blood can produce fever, how can we conceive that the whole ma.s.s could continue a minute in a putrid state without destroying life? Add to this, that putrid animal substances give up air, as in gangrenes; and that hence if the blood was putrid, air should be given out, which in the blood-vessels is known to occasion immediate death.

In these sensitive fevers with strong pulse (or inflammations) there are two sensorial faculties concerned in producing the disease, viz. irritation and sensation; and hence, as their combined action is more violent, the general quant.i.ty of sensorial power becomes further exhausted during the exacerbation, and the system more rapidly weakened than in irritative fever with strong pulse; where the spirit of animation is weakened by but one mode of its exertion: so that this febris sensitiva pulsu forti (or inflammatory fever,) may be considered as the febris irritativa pulsu forti, with the addition of inflammation; and the febris sensitiva pulsu debili (or malignant fever) may be considered as the febris irritativa pulsu debili (or nervous fever), with the addition of inflammation.

4. In these putrid or malignant fevers a deficiency of irritability accompanies the increase of sensibility; and by this waste of sensorial power by the excess of sensation, which was already too small, arises the delirium and stupor which so perpetually attend these inflammatory fevers with arterial debility. In these cases the voluntary power first ceases to act from deficiency of sensorial spirit; and the stimuli from external bodies have no effect on the exhausted sensorial power, and a delirium like a dream is the consequence. At length the internal stimuli cease to excite sufficient irritation, and the secretions are either not produced at all, or too parsimonious in quant.i.ty. Amongst these the secretion of the brain, or production of the sensorial power, becomes deficient, till at last all sensorial power ceases, except what is just necessary to perform the vital motions, and a stupor succeeds; which is thus owing to the same cause as the preceding delirium exerted in a greater degree.

This kind of delirium is owing to a suspension of volition, and to the disobedience of the senses to external stimuli, and is always occasioned by great debility, or paucity of sensorial power; it is therefore a bad sign at the end of inflammatory fevers, which had previous arterial strength, as rheumatism, or pleurisy, as it shews the presence of great exhaustion of sensorial power in a system, which having lately been exposed to great excitement, is not so liable to be stimulated into its healthy action, either by additional stimulus of food and medicines, or by the acc.u.mulation of sensorial power during its present torpor. In inflammatory fevers with debility, as those termed putrid fevers, delirium is sometimes, as well as stupor, rather a favourable sign; as less sensorial power is wasted during its continuance (see Cla.s.s II. 1. 6. 8.), and the const.i.tution not having been previously exposed to excess of stimulation, is more liable to be excited after previous quiescence.

When the sum of general pleasurable sensation becomes too great, another kind of delirium supervenes, and the ideas thus excited are mistaken for the irritations of external objects: such a delirium is produced for a time by intoxicating drugs, as fermented liquors, or opium: a permanent delirium of this kind is sometimes induced by the pleasures of inordinate vanity, or by the enthusiastic hopes of heaven. In these cases the power of volition is incapable of exertion, and in a great degree the external senses become incapable of perceiving their adapted stimuli, because the whole sensorial power is employed or expended on the ideas excited by pleasurable sensation.

This kind of delirium is distinguished from that which attends the fevers above mentioned from its not being accompanied with general debility, but simply with excess of pleasurable sensation; and is therefore in some measure allied to madness or to reverie; it differs from the delirium of dreams, as in this the power of volition is not totally suspended, nor are the senses precluded from external stimulation; there is therefore a degree of consistency, in this kind of delirium, and a degree of attention to external objects, neither of which exist in the delirium of fevers or in dreams.

5. It would appear, that the vascular system of other animals are less liable to be put into action by their general sum of pleasurable or painful sensation; and that the trains of their ideas, and the muscular motions usually a.s.sociated with them, are less powerfully connected than in the human system. For other animals neither weep, nor smile, nor laugh; and are hence seldom subject to delirium, as treated of in Sect. XVI. on Instinct.

Now as our epidemic and contagious diseases are probably produced by disagreeable sensation, and not simply by irritation; there appears a reason, why brute animals are less liable to epidemic or contagious diseases; and secondly, why none of our contagions, as the small-pox or measles, can be communicated to them, though one of theirs, viz. the hydrophobia, as well as many of their poisons, as those of snakes and of in insects, communicate their deleterious or painful effects to mankind.