Whence it appears, that in fevers with weak pulse, if the action of the heart, arteries, and capillaries could be diminished, or stopped for a short time without occasioning the death of the patient, as happens in cold bathing, or to persons apparently drowned, that a great acc.u.mulation of the sensorial powers of irritation or of a.s.sociation might soon be produced, and the pulse become stronger, and consequently slower, and the fever cease. Hence cold ablution may be of service in fevers with weak pulse, by preventing the expenditure and producing acc.u.mulation of the sensorial power of irritation or a.s.sociation. Stupor may be useful on the same account. Could a centrifugal swing be serviceable for this purpose, either by placing the head or the feet in the outward part of the circle, as described in Art. 15. 7. of this Supplement?

IV. _Return of the cold Fit._

1. If the increased action of the cutaneous and pulmonary capillaries, and of the heart and arteries, in febris irritativa continues long and with violence, a proportional expenditure or exhaustion of sensorial power occurs; which by its tendency to induce torpor of some part, or of the whole, brings on a return of the cold fit.

2. Another cause which contributes to induce torpor of the whole system by the sympathy of its parts with each other, is the remaining torpor of some viscus; which after the last cold paroxysm had not recovered itself, as of the spleen, liver, kidnies, or of the stomach and intestines, or absorbent vessels, as above mentioned.

3. Other causes are the deficiency of the natural stimuli, as hunger, thirst, and want of fresh air. Other causes are great fatigue, want of rest, fear, grief, or anxiety of mind. And lastly, the influence of external ethereal fluids, as the defect of external heat, and of solar or lunar gravitation. Of the latter the return of the paroxysms of continued fevers about six o'clock in the evening, when the solar gravitation is the least, affords an example of the influence of it; and the usual periods of intermittents, whether quotidian, tertian, or quartan, which so regularly obey solar or lunar days, afford instances of the influence of those luminaries on these kinds of fevers.

4. If the tendency to torpor of some viscus is considerable, this will be increased at the time, when the terrene gravitation is greatest, as explained in the introduction to Cla.s.s IV. 2. 4. and may either produce a cold paroxysm of quotidian fever; or it may not yet be sufficient in quant.i.ty for that purpose, but may nevertheless become greater, and continue so till the next period of the greatest terrene gravitation, and may then either produce a paroxysm of tertian fever; or may still become greater, and continue so till the next period of greatest terrene gravitation, and then produce a paroxysm of quartan ague. And lastly, the periodical times of these paroxysms may exceed, or fall short of, the time of greatest diurnal terrene gravitation according to the time of day, or period of the moon, in which the first fit began; that is, whether the diurnal terrene gravitation was then in an increasing or decreasing state.

V. _Sensation excited in Fever._

1. A curious observation is related by Dr. Fordyce in his Tract on Simple fever, page 168. He a.s.serts, that those people, who have been confined some time in a very warm atmosphere, as of 120 or 130 degrees of heat, do not feel cold, nor are subject to paleness of their skins, on coming into a temperature of 30 or 40 degrees; which would produce great paleness and painful sensation of coldness in those, who had been some time confined in an atmosphere of only 86 or 90 degrees. a.n.a.logous to this, an observing friend of mine a.s.sured me, that once having sat up to a very late hour with three or four very ingenious and humorous companions, and drank a considerable quant.i.ty of wine; both contrary to his usual habits of life; and being obliged to rise early, and to ride a long journey on the next day; he expected to have found himself weak and soon fatigued; but on the contrary he performed his journey with unusual ease and alacrity; and frequently laughed, as he rode, at the wit of the preceding evening. In both these cases a degree of pain or pleasure actuated the system; and thus a sensorial power, that of sensation, was superadded to that of irritation, or volition. See Sect. x.x.xIV. 2. 6.

2. Similar to this, when the energetic exertions of some parts of the system in the hot fit of fever arise to a certain excess, a degree of sensation is produced; as of heat, which particularly increases the actions of the cutaneous vessels, which are more liable to be excited by this stimulus. When this additional sensorial power of sensation exists to a greater degree, the pulse, which was before full, now becomes hard, owing to the inflammation of the vasa vasorum, or coats of the arteries. In these cases, whether there is any topical inflammation or not, the fever ceases to intermit; but nevertheless there are daily remissions and exacerbations of it; which recur for the most part about six in the evening, when the solar gravitation is the least, as mentioned in Sect. x.x.xVI. 3. 7.

3. Thus the introduction of another sensorial power, that of sensation, converts an intermittent fever into a continued one. If it be attended with strong pulse, it is termed febris sensitiva irritata, or pyrexia, or inflammation; if with a weak pulse, it is termed febris sensitiva inirritata, or typhus gravior, or malignant fever. The seat of the inflammation is in the glandular or capillary system, as it consists in the secretion of new fluids, or new fibres, which form new vessels, as they harden, like the silk of the silk-worm. See Art. 15. of this Supplement.

VI. _Circles of irritative a.s.sociate Motions._

1. There are some a.s.sociate motions, which are perpetually proceeding in our waking hours, and are catenated by their first link, or in some subsequent parts of the chain, with the stimuli or the influence of external things; which we shall here enumerate, as they contribute to the knowledge of fever. Of these are the irritative ideas, or sensual motions of the organs of sense, and the muscular motions a.s.sociated with them; which, when the chain is disturbed or interrupted, excite the sensorial power of sensation, and proceed in confusion. Thus if the irritative ideas of sight are disturbed, the paralactic motions of objects, which in general are unperceived, become sensible to us; and the locomotive muscles a.s.sociated with them, which ought to preserve the body erect, stagger from this decrease or interruption of the sensorial power of a.s.sociation; and vertigo is produced.

When the irritative sensual motions, or ideas, belonging to one sense are increased or diminished, the irritative sensual motions, or ideas, of the other senses are liable to become disturbed by their general catenations; whence occur noises in the ears, bad tastes in the mouth, bad odours, and numbness or tingling of the limbs, as a greater or less number of senses are affected. These const.i.tute concomitant circles of disturbed irritative ideas; or make a part of the great circle of irritative ideas, or motions of the organs of sense; and when thus disturbed occasion many kinds of hallucination of our other senses, or attend on the vertigo of vision.

2. Another great circle of irritative a.s.sociated motions consists of those of the alimentary ca.n.a.l; which are catenated with stimuli or with influences external to the system, but continue to be exerted in our sleeping as well as in our waking hours. When these a.s.sociations of motion are disturbed by the too great or too small stimulus of the food taken into the stomach, or by the too great excess or deprivation of heat, or by indigestible substances, or by torpor or o.r.g.a.s.m occasioned by their a.s.sociation with other parts, various diseases are induced under the names of apepsia, hypochondriasis, hysteria, diarrhoea, cholera, ileus, nephritis, fever.

3. A third circle of irritative a.s.sociate motions consists of those of the absorbent system; which may be divided into two, the lacteals, and the lymphatics. When the stomach and intestines are recently filled with food and fluid, the lacteal system is stimulated into great action; at the same time the cellular, cutaneous, and pulmonary lymphatics act with less energy; because less fluid is then wanted from those branches, and because more sensorial power is expended by the lacteal branch. On this account these two systems of absorbents are liable to act by reverse sympathy; hence pale urine is made after a full dinner, as less of the aqueous part of it is imbibed by the urinary lymphatics; and hence the water in anasarca of the lungs and limbs is speedily absorbed, when the actions of the lacteals of the stomach or intestines are weakened or inverted by the exhibition of those drugs, which produce nausea, or by violent vomiting, or violent cathartics.

Hence in diabetes the lacteal system acts strongly, at the same time that the urinary lymphatics invert their motions, and transmit the chyle into the bladder; and in diarrhoea from c.r.a.pula, or too great a quant.i.ty of food and fluid taken at a time, the lacteals act strongly, and absorb chyle or fluids from the stomach and upper intestines; while the lymphatics of the lower intestines revert their motions, and transmit this over-repletion into the lower intestines, and thus produce diarrhoea; which accounts for the speedy operation of some cathartic drugs, when much fluid is taken along with them.

4. Other circles of irritative a.s.sociate motions of great importance are those of the secerning system; of these are the motions of the larger congeries of glands, which form the liver, spleen, pancreas, gastric glands, kidneys, salivary glands, and many others; some of which act by direct and others by reverse sympathy with each other. Thus when the gastric glands act most powerfully, as when the stomach is filled with food, the kidneys act with less energy; as is shewn by the small secretion of urine for the first hour or two after dinner; which reverse sympathy is occasioned by the greater expenditure of sensorial power on the gastric glands, and to the newly absorbed fluids not yet being sufficiently animalized, or otherwise prepared, to stimulate the secretory vessels of the kidneys.

But those very extensive glands, which secrete the perspirable matter of the skin and lungs, with the mucus, which lubricates all the internal cells and cavities of the body, claim our particular attention. These glands, as well as all the others, proceed from the capillary vessels, which unite the arteries with the veins, and are not properly a part of them; the mucous and perspirative glands, which arise from the cutaneous and pulmonary capillaries, are a.s.sociated by direct sympathy; as appears from immersion in the cold bath, which is therefore attended with a temporary difficult respiration; while those from the capillaries of the stomach and heart and arteries are more generally a.s.sociated by reverse sympathy with those of the cutaneous capillaries; as appears in fevers with weak pulse and indigestion, and at the same time with a hot and dry skin.

The disturbed actions of this circle of the a.s.sociate motions of the secerning system, when the sensorial power of sensation is added to that of irritation, frequently produces inflammation, which consists in the secretion of new fluids or new vessels. Nevertheless, if these disturbed actions be of the torpid kind, the pain, which attends them, is seldom productive of inflammation, as in hemicrania; but is liable to excite voluntary actions, and thus to expend much sensorial power, as in the shuddering in cold fits of fever, or in convulsions; or lastly the pain itself, which attends torpid actions, is liable to expend or exhaust much sensorial power without producing any increased actions; whence the low pulse, and cold extremities, which usually attend hemicrania; and hence when inert, or inactive sensation attends one link of a.s.sociated action, the succeeding link is generally rendered torpid, as a coldness of the cheek attends tooth-ach.

5. A fifth important circle of irritative motions is that of the sanguiferous system, in which the capillary vessels are to be included, which unite the arterial and venous systems, both pulmonary and aortal. The disturbed action of this system of the heart and arteries, and capillaries, const.i.tute simple fever; to which may be added, that the secerning and absorbent vessels appending to the capillaries, and the bibulous mouths of the veins, are in some measure at the same time generally affected.

6. Now, though the links of each of these circles of irritative motions are more strictly a.s.sociated together, yet are they in greater or less degree a.s.sociated or catenated with each other by direct or reverse sympathy. Thus the sickness, or inverted irritative motions of the stomach, are a.s.sociated or catenated with the disturbed irritative ideas, or sensual motions, in vertigo; as in sea-sickness. This sickness of the stomach is also a.s.sociated or catenated with the torpor of the heart and arteries by direct sympathy, and with the capillaries and absorbents by reverse sympathy; and are thus all of them liable occasionally to be disturbed, when one of them is diseased; and const.i.tute the great variety of the kinds or symptoms of fevers.

VII. _Alternation of the cold and hot Fits._

1. When any cause occurs, which diminishes to a certain degree the supply of sensorial power in respect to the whole system; as suppose a temporary inexertion of the brain; what happens? First, those motions are exerted with less energy, which are not immediately necessary to life, as the locomotive muscles; and those ideas, which are generally excited by volition; at the same time this deficiency of voluntary motion is different from that which occurs in sleep; as in that the movements of the arterial system are increased in energy though not in frequency. Next, the motions of the alimentary ca.n.a.l become performed with less energy, or cease altogether; and a total want of appet.i.te to solid food occurs, or sickness, or a diarrhoea occasioned by the indigested aliment. Then the absorbent vessels cease to act with their due energy; whence thirst, and pale urine, though in small quant.i.ties. Fourthly, the secerning vessels become affected by the general diminution of sensorial power; whence all the secreted fluids are produced in less quant.i.ty. And lastly, the sanguiferous ca.n.a.ls feel the general torpor; the pulsations of the heart and arteries become feeble, and consequently quick; and the capillaries of the skin become inactive, acquire less blood from the arteries, and are consequently paler and shrunk.

In this last circ.u.mstance of the torpor of the sanguiferous system consists inirritative fever; as all the others are rather accidental or concomitant symptoms, and not essential ones; as fewer or more of them may be present, or may exist with a greater or less degree of inactivity.

2. Now as the capillaries of the skin are exposed to greater varieties of heat and cold, than the heart and arteries, they are supposed to be more mobile, that is, more susceptible of torpor or exertion, or to inflammation, by external stimuli or influences, than the other parts of the sanguiferous system; and as the skin is more sensible to the presence of heat, than the internal parts of the body, the commencement of the cold paroxysms of fever generally either first exists in, or is first perceived by, the coldness and paleness of the skin; and the commencement of the hot fits by the heat and redness of it.

3. The acc.u.mulation of sensorial power occurs in these organs soonest, and in greatest quant.i.ty, during their quiescence, which were most perpetually in action during health; hence those parts of the system soonest recover from torpor in intermittent fever, and soonest fall into the contrary extreme of increased activity; as the sanguiferous system of the heart and arteries and capillaries. But of these the capillaries seem first to acquire a renovation of their action, as the heat of the skin becomes first renewed, as well as increased beyond its natural quant.i.ty, and this in some parts sooner than in others; which quant.i.ty of heat is however not to be estimated simply by the rise of the mercury in the thermometer, but also by the quant.i.ty carried away into the atmosphere, or diffused amongst other bodies in a given time; as more heat pa.s.ses through water, which boils vehemently, than when it boils gently, though the rise of the thermometer in both cases continues the same. This fact may be known by boiling an egg in water, the white of which coagulates in much less time, if the water boils vehemently, than if it boils moderately, though the sensible heat of the water is the same in both cases.

Another cause, which induces the cutaneous capillaries to renew their actions sooner than the heart and arteries after immersion in the cold bath, is, that their torpor was occasioned by defect of irritation; whereas that of the heart and arteries was occasioned by defect of a.s.sociation; which defect of a.s.sociation was owing to the decreased actions of the capillaries, and is now again excited by their renewed action; which excitement must therefore be subsequent to that increased action of the capillaries; and in consequence the increased action of the heart and arteries at the commencement of the hot fit of some fevers is subsequent to the increased action of the cutaneous capillaries. There is, however, in this case an acc.u.mulation of the sensorial power of a.s.sociation in the heart and arteries, which must contribute to increase their o.r.g.a.s.m in the hot fit, as well as the increased excitement of it by the increased action of the capillaries.

4. Now this increased action of the system, during the hot fit, by exhausting the sensorial powers of irritation and a.s.sociation, contributes to induce a renewal of the cold paroxysm; as the acc.u.mulation of those sensorial powers in the cold fit produces the increased actions of the hot fit; which two states of the system reciprocally induce each other by a kind of libration, or a plus and minus, of the sensorial powers of irritation and a.s.sociation.

If the exhaustion of sensorial power during the hot fit of fever only reduces the quant.i.ty of irritability and a.s.sociability to its natural standard, the fever is cured, not being liable to return. If the quant.i.ty of these sensorial powers be reduced only so much, as not to produce a second cold fit during the present quant.i.ty of external stimuli or influences; yet it may be so far reduced, that a very small subtraction of stimulus, or of influence, may again induce a cold fit; such as the coldness of the night-air, or the diminution of solar or lunar gravitation, as in intermittent fevers.

5. Another cause of the renovation of the cold fits of fever is from some parts of the system not having completely recovered from the former cold paroxysm; as happens to the spleen, liver, or other internal viscus; which sometimes remains tumid, and either occasions a return of the cold fit by direct sympathy with other parts of the body, or by its own want of action causes a diminution of the general quant.i.ty of heat, and thus facilitates the renovation of the torpor of the whole system, and gives cause to intermittent fevers catenated with lunar or solar influence.

VIII. _o.r.g.a.s.m of the Capillaries._

As the remaining torpor of some less essential part of the system, as of the spleen, when the hot fit ceases, produces after one, two, or three days a return of cold fit by direct sympathy with the cutaneous capillaries, when joined with some other cause of torpor, as the defect of solar or lunar influences, or the exposure to cold or hunger, and thus gives origin to intermittent fever; so the remaining torpor of some more essential parts of the system, as of the stomach and intestines, is probably the cause of the immediate recurrence of the cold paroxysm, at the time the hot one ceases, by their direct sympathy with the cutaneous capillaries, without the a.s.sistance of any other cause of torpor; and thus produces remittent fever. And lastly the remaining torpor of some still more essential parts of the system, as the heart and arteries, after the hot fit ought to cease, is liable by reverse sympathy with the cutaneous capillaries to continue their o.r.g.a.s.m, and thus to render a fever continual, which would otherwise remit or intermit.

Many difficulties here occur, which we shall endeavour to throw some light upon, and leave to future investigation; observing only that difficulties were to be expected, otherwise fevers would long since have been understood, as they have employed the unremitted attention of the physicians of all ages of the world.

1. Why do the same parts of successive trains of action sometimes affect each other by direct, and sometimes by reverse sympathy?--1st, When any irritative motion ceases, or becomes torpid, which was before in perpetual action; it is either deprived of its usual stimulus, and thence the sensorial power of irritation is not excited; or it has been previously too much stimulated, and the sensorial power has been thus exhausted.

In the former case an acc.u.mulation of sensorial power soon occurs, which is excitable by a renewal of the stimulus; as when the fingers, which have been immersed some time in snow, are again exposed to the usual warmth of a room. Or, secondly, the sensorial power of irritation becomes so much acc.u.mulated, that the motions, which were torpid, are now performed by less stimulus than natural; as appears by the warmth, which soon occurs after the first chill in going into frosty air, or into the bath at Buxton, which is about eighty degrees of heat. Or, lastly, this acc.u.mulation of the sensorial power of irritation so far abounds, that it increases the action of the next link of the a.s.sociated train or tribe of motions; thus on exposing the skin to cold air, as in walking out in a frosty morning, the actions of the stomach are increased, and digestion strengthened.

But where the torpor of some irritative motion is owing to the previous exhaustion of the sensorial power of irritation by too great stimulus, the restoration of it occurs either not at all, or much more slowly than in the former instances; thus after intoxication the stomach is very slow in recovering its due quant.i.ty of the sensorial power of irritation, and never shews any acc.u.mulation of it.

2. When an a.s.sociate motion, as described in the introduction to Cla.s.s IV.

1. 1. acts with less energy, the sensorial power of a.s.sociation is either not sufficiently excited by the preceding fibrous motions; or it has been expended or exhausted by the too violent actions of the preceding fibrous motions. In the former case there occurs an acc.u.mulation of the sensorial power of a.s.sociation; exactly as, where the usual stimulus is withdrawn, there occurs an acc.u.mulation of the sensorial power of irritation. Thus when the actions of the capillaries of the skin are diminished by immersion in cold water, the capillaries of the lungs are rendered torpid by the want of the excitement of the sensorial power of a.s.sociation, owing to the lessened actions of the previous fibrous motions, namely, of those of the skin. Nevertheless as soon as the capillaries of the skin regain their increased activity by the acc.u.mulation of the sensorial power of irritation, these capillaries of the lungs act with greater energy also owing to their acc.u.mulated sensorial power of a.s.sociation. These are instances of direct sympathy, and const.i.tute the cold and hot paroxysms of intermittent fever; or the first paroxysm of a continued one.

3. When the first link of a train of a.s.sociated motions, which is subject to perpetual action, becomes a considerable time torpid for want of being excited by the previous exertions of the irritative motions, with which it is catenated; the sensorial power of a.s.sociation becomes acc.u.mulated in so great a degree as to affect the second link of the train of a.s.sociated motions, and to excite it into stronger action. Thus when the stomach is rendered torpid by contagious matter swallowed into it mixed with the saliva, the heart and arteries act more feebly; because the sensorial power of a.s.sociation, which used to be excited by the fibrous motions of the stomach, is not now excited; and in consequence the motions of the heart and arteries act only by the sensorial power of irritation, which is excited by the stimulus of the blood.

But during this torpor of the stomach, and less action of the heart and arteries, so great an acc.u.mulation of the sensorial powers of irritation and of a.s.sociation occurs, that it adds to the action of the next link of this vital circle of actions, that is, to that of the cutaneous capillaries. Whence in this situation the torpor of the stomach occasions a diminished action of the heart and arteries by direct sympathy, and may be said to occasion an increased one of the cutaneous capillaries by reverse sympathy; which const.i.tute continued fever with weak pulse.

Nor is this increased action of the capillaries in consequence of the decreased action of the heart and arteries, as in fevers with weak pulse, a single fact in the animal economy; though it exists in this case in the greatest degree or duration, because the heart and arteries are perpetually in greater action than any other part of the system. But a similar circ.u.mstance occurs, when the stomach is rendered inactive by defective excitement of the sensorial power of a.s.sociation, as in sea-sickness, or in nephritis. In these cases the sensorial power of a.s.sociation becomes much acc.u.mulated in the stomach, and seems by its superabundance to excite the absorbent system, which is so nearly connected with it, into great increase of action; as is known by the great quant.i.ty frequently in these situations rejected by vomit, which could not otherways be supplied. It is probable the increase of digestion by walking in frosty air, with many other animal facts, may by future observations be found to be dependent on this principle, as well as the increased action of the capillaries in continued fevers with weak pulse.

Whereas in continued fever with strong pulse, which may perhaps occur sometimes on the first day even of the plague, the stomach with the heart and arteries and the capillaries act by direct sympathy; that is, the stomach is excited into stronger action by increased irritation owing to the stimulus of contagious matter; these stronger irritative motions of the stomach excite a greater quant.i.ty of the sensorial power of a.s.sociation, which then actuates the heart and arteries with greater energy, as these are catenated with the stomach; and in the same manner the increased actions of the heart and arteries excite a greater quant.i.ty of the sensorial power of a.s.sociation, which actuates the cutaneous capillaries with increase of energy. See Cla.s.s IV. 1. 1.

4. I shall dwell a little longer on this intricate subject. The commencement of fever-fits is known by the inactivity of the cutaneous capillaries, which inactivity is observable by the paleness and coldness of the skin, and also by the pain of coldness, which attends it. There is nevertheless in most cases, except those which are owing to exposure to external cold, a torpor of the capillaries of some internal viscus preceding this inactivity of the cutaneous capillaries; which is known, by the tumour or hardness of the viscus, or by an aching pain of it. The capillaries of the lungs are at the same time rendered inactive or torpid, as appears by the difficulty of breathing, and coldness of the breath in cold fits of fever, and in going into the cold bath; but the lungs are not affected with the pain either of coldness or of torpor.

One cause of this synchronous or successive inactivity of the cutaneous capillaries, in consequence of the previous torpor of some internal viscus, may be owing to the deficiency of heat; which must occur, when any part becomes inactive; because the secretions of that part cease or are lessened, and the quant.i.ty of heat of it in consequence. But the princ.i.p.al cause of it I suppose to be owing to the defect of the sensorial power of a.s.sociation; which power of a.s.sociation is excited by some previous or concomitant motions of the parts of every great circle of actions. This appears on going into the cold bath, because the shortness of breath instantly occurs, sooner than one can conceive the diminution of the heat of the skin could affect the lungs by the want of its stimulus; but not sooner than the defect of the sensorial power of a.s.sociation could affect them; because this must cease to be excited into action on the instant that the cutaneous capillaries cease to act; whence in the first moment of contact of the cold water the cutaneous capillaries cease to act from defect of irritation; which is caused by defect of the stimulus of heat; and in the second moment the capillaries of the lungs cease to act from the defect of a.s.sociation; which is caused by the defect of the motions of the cutaneous capillaries. Thus the universal torpor in the cold paroxysm of fever is an example of direct sympathy, though occasioned in part by defect of irritation, and in part by defect of a.s.sociation.

5. Thus in walking out in a frosty morning the skin is cooled by the contact of the cold air, whence the actions of its capillaries are diminished for want of their usual stimulus of heat to excite a sufficient quant.i.ty of the sensorial power of irritation. Hence there is at first a saving of sensorial power of irritation for the purpose of actuating the other parts of the system with greater energy. Secondly the sensorial power of a.s.sociation, which used to be excited by the motions of the cutaneous capillaries, is now not so powerfully excited; and in consequence the parts, which const.i.tute the next links of the circles of a.s.sociated motions, are for a time actuated with less energy, and a temporary general chillness succeeds; which is so far similar to the cold fit of intermittent fever.

In this situation there is a curious circ.u.mstance occurs, which merits peculiar attention: after a short time, though the external skin continues cool by its exposure to the cold air, and the actions of its capillaries are consequently diminished, yet the capillaries of the stomach act with greater energy; as is known by increased digestion and consequent hunger.

This is to be ascribed to the acc.u.mulation of the sensorial power of irritation, which now excites by its superabundance, or overflowing, as it were, the stomach into increased action; though it is at the same time excited less powerfully than usual by the sensorial power of a.s.sociation.

Thus the acc.u.mulation of the sensorial power of irritation in the vessels of the skin increases in this case the action of the stomach, in the same manner as an acc.u.mulation of the sensorial power of a.s.sociation in the heart and arteries in fevers with weak pulse increases the action of the capillaries.

If nevertheless the coldness of the skin be too long continued, or exists in too great a degree, so as in some measure to impair the life of the part, no further acc.u.mulation of the sensorial power of irritation occurs; and in consequence the actions of the stomach become less than natural by the defect of the sensorial power of a.s.sociation; which has ceased to be excited by the want of action of the cutaneous capillaries. Whence continued coldness of the feet is accompanied with indigestion and heartburn. See Cla.s.s IV. 2. 1. 6.

6. Similar to this when the actions of the stomach are rendered torpid by the previous stimulus of a violent emetic, and its motions become retrograde in consequence, a great quant.i.ty of sensorial power is exerted on the lymphatics of the lungs, and other parts of the body; which excites them into greater direct action, as is evinced by the exhibition of digitalis in anasarca. In this situation I suppose the emetic drug stimulates the muscular fibres of the stomach into too great action; and that in consequence a great torpor soon succeeds; and that this inaction of the muscular parts of the stomach is not followed by much acc.u.mulation of the sensorial power of irritation; because that sensorial power is in great measure exhausted by the previous excessive stimulus. But the lymphatics of the stomach have their actions lessened by defect of the sensorial power of a.s.sociation, which is not now excited into action, owing to the lessened motions of the muscular parts of it, with which the lymphatics are a.s.sociated. The sensorial power of a.s.sociation becomes therefore acc.u.mulated in these lymphatics of the stomach, because it is not excited into action; exactly as the power of irritation becomes acc.u.mulated in the hand, when immersed in snow; and this acc.u.mulated sensorial power of a.s.sociation excites the lymphatic of the lungs and of other parts, which are most nearly a.s.sociated with those of the stomach, into more energetic actions. Thus the muscular fibres of the stomach act with the lymphatics of that organ in direct sympathy; and the lymphatics of the stomach act in reverse sympathy with those of the lungs and of other parts of the body; the former of which is caused by defect of the excitement of the sensorial power of a.s.sociation, and the latter by the acc.u.mulation of it.

Besides the efficient cause, as above explained, the final cause, or convenience, of these organic actions are worthy our attention. In this case of an acrid drug swallowed into the stomach the reverted actions of the muscular fibres of the stomach tend to eject its enemy; the reverted actions of its lymphatics pour a great quant.i.ty of fluids into the stomach for the purpose of diluting or washing off the noxious drug; and the increased actions of the other lymphatics supply these retrograde ones of the stomach with an inconceivable supply of fluids, as is seen in Ileus and Cholera.