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ZOONOMIA;

OR,

THE LAWS

OF

ORGANIC LIFE.

VOL. II.

By ERASMUS DARWIN, M.D. F.R.S.

AUTHOR OF THE BOTANIC GARDEN.

LONDON:
PRINTED FOR. J. JOHNSON, IN ST. PAUL'S CHURCH-YARD.
1796.

Entered at Stationers' Hall.

ZOONOMIA;

OR,

THE LAWS OF ORGANIC LIFE.

PART II.

CONTAINING

A CATALOGUE OF DISEASES

DISTRIBUTED INTO

NATURAL CLASSES ACCORDING TO THEIR PROXIMATE CAUSES,

WITH THEIR

SUBSEQUENT ORDERS, GENERA, AND SPECIES,

AND WITH

THEIR METHODS OF CURE.

Hæc, ut potero, explicabo; nec tamen, quasi Pythius Apollo, certa ut sint et fixa, quæ dixero; sed ut Homunculus unus e multis probabiliora conjecturâ sequens.—Cic. Tusc. Disp. l. 1. 9.

PREFACE.

All diseases originate in the exuberance, deficiency, or retrograde action, of the faculties of the sensorium, as their proximate cause; and consist in the disordered motions of the fibres of the body, as the proximate effect of the exertions of those disordered faculties.

The sensorium possesses four distinct powers, or faculties, which are occasionally exerted, and produce all the motions of the fibrous parts of the body; these are the faculties of producing fibrous motions in consequence of irritation which is excited by external bodies; in consequence of sensation which is excited by pleasure or pain; in consequence of volition which is excited by desire or aversion; and in consequence of association which is excited by other fibrous motions. We are hence supplied with four natural classes of diseases derived from their proximate causes; which we shall term those of irritation, those of sensation, those of volition, and those of association.

In the subsequent classification of diseases I have not adhered to the methods of any of those, who have preceded me; the principal of whom are the great names of Sauvages and Cullen; but have nevertheless availed myself, as much as I could, of their definitions and distinctions.

The essential characteristic of a disease consists in its proximate cause, as is well observed by Doctor Cullen, in his Nosologia Methodica, T. ii. Prolegom. p. xxix. Similitudo quidem morborum in similitudine causæ eorum proximæ, qualiscunque sit, reverâ consistit. I have taken the proximate cause for the classic character. The characters of the orders are taken from the excess, or deficiency, or retrograde action, or other properties of the proximate cause. The genus is generally derived from the proximate effect. And the species generally from the locality of the disease in the system.

Many species in this system are termed genera in the systems of other writers; and the species of those writers are in consequence here termed varieties. Thus in Dr. Cullen's Nosologia the variola or small-pox is termed a genus, and the distinct and confluent kinds are termed species. But as the infection from the distinct kind frequently produces the confluent kind, and that of the confluent kind frequently produces the distinct; it would seem more analogous to botanical arrangement, which these nosologists profess to imitate, to call the distinct and confluent small-pox varieties than species. Because the species of plants in botanical systems propagate others similar to themselves; which does not uniformly occur in such vegetable productions as are termed varieties.

In some other genera of nosologists the species have no analogy to each other, either in respect to their proximate cause, or to their proximate effect, though they may he somewhat similar in less essential properties; thus the thin and saline discharge from the nostrils on going into the cold air of a frosty morning, which is owing to the deficient action of the absorbent vessels of the nostrils, is one species; and the viscid mucus discharged from the secerning vessels of the same membrane, when inflamed, is another species of the same genus, Catarrhus. Which bear no analogy either in respect to their immediate cause or to their immediate effect.

The uses of the method here offered to the public of classing diseases according to their proximate causes are, first, more distinctly to understand their nature by comparing their essential properties. Secondly, to facilitate the knowledge of the methods of cure; since in natural classification of diseases the species of each genus, and indeed the genera of each order, a few perhaps excepted, require the same general medical treatment. And lastly, to discover the nature and the name of any disease previously unknown to the physician; which I am persuaded will be more readily and more certainly done by this natural system, than by the artificial classifications already published.

The common names of diseases are not well adapted to any kind of classification, and least of all to this from their proximate causes. Some of their names in common language are taken from the remote cause, as worms, stone of the bladder; others from the remote effect, as diarrhœa, salivation, hydrocephalus; others from some accidental symptom of the disease, as tooth-ach, head-ach, heart-burn; in which the pain is only a concomitant circumstance of the excess or deficiency of fibrous actions, and not the cause of them. Others again are taken from the deformity occasioned in consequence of the unnatural fibrous motions, which constitute diseases, as tumours, eruptions, extenuations; all these therefore improperly give names to diseases; and some difficulty is thus occasioned to the reader in endeavouring to discover to what class such disorders belong.

Another difficulty attending the names of diseases is, that one name frequently includes more than one disease, either existing at the same time or in succession. Thus the pain of the bowels from worms is caused by the increased action of the membrane from the stimulus of those animals; but the convulsions, which sometimes succeed these pains in children, are caused by the consequent volition, and belong to another class.

To discover under what class any disease should be arranged, we must first investigate the proximate cause; thus the pain of the tooth-ach is not the cause of any diseased motions, but the effect; the tooth-ach therefore does not belong to the class of Sensation. As the pain is caused by increased or decreased action of the membranes of the tooth, and these actions are owing to the increase or decrease of irritation, the disease is to be placed in the class of irritation.

To discover the order it must be inquired, whether the pain be owing to increased or defective motion of the pained membrane; which is known by the concomitant heat or coldness of the part. In tooth-ach without inflammation there is generally a coldness attends the cheek in its vicinity; as may be perceived by the hand of the patient himself, compared with the opposite cheek. Hence odontalgia is found to belong to the order of decreased irritation. The genus and species must be found by inspecting the synopsis of the second order of the class of Irritation. See Class I. 2. 4. 12.

This may be further elucidated by considering the natural operation of parturition; the pain is occasioned by the increased action or distention of the vessels of the uterus, in consequence of the stimulus of the fetus; and is therefore caused by increased irritation; but the action of the abdominal muscles in its exclusion are caused by the pain, and belong to the class of increased sensation. See Class II. 1. 1. 12. Hence the difficulty of determining, under what class of diseases parturition should be arranged, consists in there being two kinds of diseased actions comprehended under one word; which have each their different proximate cause.

In Sect. XXXIX. 8. 4. and in Class II. 1. 1. 1. we have endeavoured to give names to four links of animal causation, which conveniently apply to the classification of diseases; thus in common nictitation, or winking with the eyes without our attention to it, the increased irritation is the proximate cause; the stimulus of the air on the dry cornea is the remote cause; the closing of the eyelid is the proximate effect; and the diffusion of tears over the eye-ball is the remote effect. In some cases two more links of causation may be introduced; one of them may be termed the pre-remote cause; as the warmth or motion of the atmosphere, which causes greater exhalation from the cornea. And the other the post-remote effect; as the renewed pellucidity of the cornea; and thus six links of causation may be expressed in words.

But if amid these remote links of animal causation any of the four powers or faculties of the sensorium be introduced, the reasoning is not just according to the method here proposed; for these powers of the sensorium are always the proximate causes of the contractions of animal fibres; and therefore in true language cannot be termed their remote causes. From this criterion it may always be determined, whether more diseases than one are comprehended under one name; a circumstance which has much impeded the investigation of the causes, and cures of diseases.

Thus the term fever, is generally given to a collection of morbid symptoms; which are indeed so many distinct diseases, that sometimes appear together, and sometimes separately; hence it has no determinate meaning, except it signifies simply a quick pulse, which continues for some hours; in which sense it is here used.

In naming diseases I have endeavoured to avoid the affectation of making new compound Greek words, where others equally expressive could be procured: as a short periphrasis is easier to be understood, and less burthensome to the memory.

In the Methodus Medendi, which is marked by M.M. at the end of many of the species of diseases, the words incitantia, sorbentia, torpentia, &c. refer to the subsequent articles of the Materia Medica, explaining the operations of medicines.

The remote causes of many diseases, their periods, and many circumstances concerning them, are treated of in the preceding volume; the descriptions of many of them, which I have omitted for the sake of brevity, may be seen in the Nosologia Methodica of Sauvages, and in the Synopsis Nosologiæ of Dr. Cullen, and in the authors to which they refer.

In this arduous undertaking the author solicits the candour of the critical reader; as he cannot but foresee, that many errors will be discovered, many additional species will require to be inserted; and others to be transplanted, or erased. If he could expend another forty years in the practice of medicine, he makes no doubt, but that he could bring this work nearer perfection, and thence render it more worthy the attention of philosophers.——As it is, he is induced to hope, that some advantages will be derived from it to the science of medicine, and consequent utility to the public, and leaves the completion of his plan to the industry of future generations.

ZOONOMIA.

PART II.

CLASSES OF DISEASES.

The Orders and Genera of the First Class of Diseases.

CLASS I.

DISEASES OF IRRITATION.

ORDO I.

Increased Irritation.

GENERA.

ORDO II.

Decreased Irritation.

GENERA.

ORDO III.

Retrograde Irritative Motions.

GENERA.

The Orders, Genera, and Species, of the First Class of Diseases.

CLASS I.

DISEASES OF IRRITATION.

ORDO I.

Increased Irritation.

GENUS I.

With Increased Actions of the Sanguiferous System.

SPECIES.

GENUS II.

With Increased Actions of the Secerning System.

SPECIES.

GENUS III.

With increased Actions of the Absorbent System.

SPECIES.

GENUS IV.

With increased Actions of other Cavities and Membranes.

SPECIES.

GENUS V.

With increased Actions of the Organs of Sense.

SPECIES.

ORDO II.

Decreased Irritation.

GENUS I.

With decreased Actions of the Sanguiferous System.

SPECIES.

GENUS II.

With decreased Actions of the Secerning System.

SPECIES.

GENUS III.

With decreased Actions of the Absorbent System.

SPECIES.

GENUS IV.

With decreased Actions of other Cavities and Membranes.

SPECIES.

GENUS V.

With decreased Actions of the Organs of Sense.

SPECIES.

ORDO III.

Retrograde Irritative Motions.

GENUS I.

Of the Alimentary Canal.

SPECIES.

GENUS II.

Of the Absorbent System.

SPECIES.

GENUS III.

Of the Sanguiferous System.

SPECIES.

CLASS I.

DISEASES OF IRRITATION.

ORDO I.

Increased Irritation.

GENUS I.

With increased Actions of the Sanguiferous System.

The irritability of the whole, or of part, of our system is perpetually changing; these vicissitudes of irritability and of inirritability are believed to depend on the accumulation or exhaustion of the sensorial power, as their proximate cause; and on the difference of the present stimulus, and of that which we had previously been accustomed to, as their remote cause. Thus a smaller degree of heat produces pain and inflammation in our hands, after they have been for a time immersed in snow; which is owing to the accumulation of sensorial power in the moving fibres of the cutaneous vessels during their previous quiescence, when they were benumbed with cold. And we feel ourselves cold in the usual temperature of the atmosphere on coming out of a warm room; which is owing to the exhaustion of sensorial power in the moving fibres of the vessels of the skin by their previous increased activity, into which they were excited by unusual heat.

Hence the cold fits of fever are the occasion of the succeeding hot ones; and the hot fits contribute to occasion in their turn the succeeding cold ones. And though the increase of stimulus, as of heat, exercise, or distention, will produce an increased action of the stimulated fibres; in the same manner as it is produced by the increased irritability which was occasioned by a previous defect of stimulus; yet as the excesses of irritation from the stimulus of external things are more easily avoided than the deficiencies of it; the diseases of this country, except those which are the consequences of drunkenness, or of immoderate exercise, more frequently begin with torpor than with orgasm; that is, with inactivity of some parts, or of the whole of the system, and consequent coldness, than with increased activity, and consequent heat.

If the hot fit be the consequence of the cold one, it may be asked if they are proportionate to each other: it is probable that they are, where no part is destroyed by the cold fit, as in mortification or death. But we have no measure to distinguish this, except the time of their duration; whereas the extent of the torpor over a greater or less part of the system, which occasions the cold fit; or of the exertion which occasions the hot one; as well as the degree of such torpor or exertion, are perhaps more material than the time of their duration. Besides this some muscles are less liable to accumulate sensorial power during their torpor, than others, as the locomotive muscles compared with the capillary arteries; on all which accounts a long cold fit may often be followed by a short hot one.

1. Febris irritativa. Irritative fever. This is the synocha of some writers, it is attended with strong pulse without inflammation; and in this circumstance differs from the febris inirritativa of Class I. 2. 1. 1. which is attended with weak pulse without inflammation. The increased frequency of the pulsation of the heart and arteries constitutes fever; during the cold fit these pulsations are always weak, as the energy of action is then decreased throughout the whole system; and therefore the general arterial strength cannot be determined by the touch, till the cold part of the paroxysm ceases. This determination is sometimes attended with difficulty; as strong and weak are only comparative degrees of the greater or less resistance of the pulsation of the artery to the compression of the finger. But the greater or less frequency of the pulsations affords a collateral evidence in those cases, where the degree of strength is not very distinguishable, which may assist our judgment concerning it. Since a moderately strong pulse, when the patient is in a recumbent posture, and not hurried in mind, seldom exceeds 120 strokes in a minute; whereas a weak one often exceeds 130 in a recumbent posture, and 150 in an erect one, in those fevers, which are termed nervous or putrid. See Sect. XII. 1. 4.

The increased frequency of the pulsation of the heart and arteries, as it is occasioned either by excess or defect of stimulus, or of sensorial power, exists both in the cold and hot fits of fever; but when the cold fit ceases, and the pulse becomes strong and full as well as quick, in consequence of the increased irritability of the heart and arteries, it constitutes the irritative fever, or synocha. It is attended with considerable heat during the paroxysm, and generally terminates in a quarter of a lunation, without any disturbance of the faculties of the mind. See Class IV. 1. 1. 8.

M. M. Venesection. Emetics. Cathartics. Cool the patient in the hot fit, and warm him in the cold one. Rest. Torpentia.

2. Ebrietas. Drunkenness. By the stimulus of wine or opium the whole arterial system, as well as every other part of the moving system, is excited into increased action. All the secretions, and with them the production of sensorial power itself in the brain, seem to be for a time increased, with an additional quantity of heat, and of pleasureable sensation. See Sect. XXI. on this subject. This explains, why at the commencement of the warm paroxysm of some fevers the patient is in greater spirits, or vivacity; because, as in drunkenness, the irritative motions are all increased, and a greater production of sensation is the consequence, which when in a certain degree, is pleasureable, as in the diurnal fever of weak people. Sect. XXXVI. 3. 1.

3. Hæmorrhagia arteriosa. Arterial hæmorrhage. Bleeding with a quick, strong, and full pulse. The hæmorrhages from the lungs, and from the nose, are the most frequent of these; but it sometimes happens, that a small artery but half divided, or the puncture of a leech, will continue to bleed pertinaciously.

M. M. Venesection. Cathartic with calomel. Divide the wounded artery. Bind sponge on the puncture. If coffee or charcoal internally? If air with less oxygen?

4. Hæmoptoe arteriosa. Spitting of arterial blood. Blood spit up from the lungs is florid, because it has just been exposed to the influence of the air in its passage through the extremities of the pulmonary artery; it is frothy, from the admixture of air with it in the bronchia. The patients frequently vomit at the same time from the disagreeable titillation of blood about the fauces; and are thence liable to believe, that the blood is rejected from the stomach.

Sometimes an hæmoptoe for several successive days returns in gouty persons without danger, and seems to supply the place of the gouty paroxysms. Is not the liver always diseased previous to the hæmoptoe, as in several other hæmorrhages? See Class I. 2. 1. 9.

M. M. Venesection, a purge, a blister, diluents, torpentia; and afterwards sorbentia, as the bark, the acid of vitriol, and opium. An emetic is said to stop a pulmonary hæmorrhage, which it may effect, as sickness decreases the circulation, as is very evident in the great sickness sometimes produced by too large a dose of digitalis purpurea.

Dr. Rush says, a table spoonful or two of common salt is successful in hæmoptoe; this may be owing to its stimulating the absorbent systems, both the lymphatic, and the venous. Should the patient respire air with less oxygen? or be made sick by whirling round in a chair suspended by a rope? One immersion in cold water, or a sudden sprinkling all over with cold water, would probably stop a pulmonary hæmorrhage. See Sect. XXVII. 1.

5. Hæmorrhagia narium. Epistaxis. Bleeding at the nose in elderly subjects most frequently attends those, whose livers are enlarged or inflamed by the too frequent use of fermented liquors.

In boys it occurs perhaps simply from redundancy of blood; and in young girls sometimes precedes the approach of the catamenia; and then it shews a disposition contrary to chlorosis; which arises from a deficiency of red blood.

M. M. It is stopped by plunging the head into cold water, with powdered salt hastily dissolved in it; or sometimes by lint strewed over with wheat flour put up the nostrils; or by a solution of steel in brandy applied to the vessel by means of lint. The cure in other respects as in hæmoptoe; when the bleeding recurs at certain periods, after venesection, and evacuation by calomel, and a blister, the bark and steel must be given, as in intermittent fevers. See Section XXVII. 1.

ORDO I.

Increased Irritation.

GENUS II.

With increased Actions of the Secerning System.

These are always attended with increase of partial or of general heat; for the secreted fluids are not simply separated from the blood, but are new combinations; as they did not previously exist as such in the blood vessels. But all new combinations give out heat chemically; hence the origin of animal heat, which is always increased in proportion to the secretion of the part affected, or to the general quantity of the secretions. Nevertheless there is reason to believe, that as we have a sense purposely to distinguish the presence of greater or less quantities of heat, as mentioned in Sect. XIV. 6. so we may have certain minute glands for the secretion of this fluid, as the brain is believed to secrete the sensorial power, which would more easily account for the instantaneous production of the blush of shame, and of anger. This subject deserves further investigation.

SPECIES.

1. Calor febrilis. The heat in fevers arises from the increase of some secretion, either of the natural fluids, as in irritative fevers; or of new fluids, as in infectious fevers; or of new vessels, as in inflammatory fevers. The pain of heat is a consequence of the increased extension or contraction of the fibres exposed to so great a stimulus. See Class I. 1. 5. 6.

2. Rubor febrilis. Febrile redness. When the cold fit of fever terminates, and the pulsations of the heart and arteries become strong as well as quick from the increase of their irritability after their late quiescence, the blood is impelled forwards into the fine extremities of the arteries, and the anastomozing capillaries, quicker than the extremities of the veins can absorb and return it to the heart. Hence the pulse at the wrist becomes full, as well as quick and strong, and the skin glows with arterial blood, and the veins become empty and less visible.

In elderly people the force of the heart and arteries becomes less, while the absorbent power of the veins remains the same; whence the capillary vessels part with the blood, as soon as it is received, and the skin in consequence becomes paler; it is also probable, that in more advanced life some of the finer branches of the arteries coalesce, and become impervious, and thus add to the opacity of the skin.

3. Sudor calidus. Warm sweat may be divided into four varieties, according to their remote causes. First, the perspirable matter is secreted in as great quantity during the hot fit of fever, as towards the end of it, when the sweat is seen upon the skin. But during the hot fit the cutaneous absorbents act also with increased energy, and the exhalation is likewise increased by the greater heat of the skin; and hence it does not appear in drops on the surface, but is in part reabsorbed, and in part dissipated in the atmosphere. But as the mouths of the cutaneous absorbents are exposed to the cool air or bedclothes; whilst those of the capillary glands, which secrete the perspirable matter, are exposed to the warmth of the circulating blood; the former, as soon as the fever-fit begins to decline, lose their increased action first; and hence the absorption of the sweat is diminished, whilst the increased secretion of it continues for some hours afterwards, which occasions it to stand in drops upon the skin.

As the skin becomes cooler, the evaporation of the perspirable matter becomes less, as well as the absorption of it. And hence the dissipation of aqueous fluid from the body, and the consequent thirst, are perhaps greater during the hot fit, than during the subsequent sweat. For the sweats do not occur, according to Dr. Alexander's experiments, till the skin is cooled from 112 to 108 degrees of heat; that is, till the paroxysm begins to decline. From this it appears, that the sweats are not critical to the hot fit, any more than the hot fit can be called critical to the cold one; but simply, that they are the natural consequence of the decline of the hot fit, commencing with the decreased action of the absorbent system, and the decreased evaporation from the skin. And from hence it may be concluded, that a fever-fit is not in general an effort of nature to restore health, as Sydenham considered it, but a necessary consequence of the previous torpor; and that the causes of fevers would be less detrimental, if the fever itself could be prevented from existing; as appears in the cool treatment of the small-pox.

It must be noted that the profuse sweats on the skin are more frequent at the decline of fever-fits than the copious urine, or loose stools, which are mentioned below; as the cutaneous absorbents, being exposed to the cool air, lose their increased action sooner than the urinary or intestinal absorbents; which open into the warm cavities of the bladder and intestines; but which are nevertheless often affected by their sympathy with the cutaneous absorbents. Hence few fevers terminate without a moisture of the skin; whence arose the fatal practice of forcing sweats by the external warmth of air or bedclothes in fevers; for external warmth increases the action of the cutaneous capillaries more than that of the other secerning vessels; because the latter are habituated to 98 degrees of heat, the internal warmth of the body; whereas the cutaneous capillaries being nearer the surface are habitually kept cooler by the contact of the external air. Sweats thus produced by heat in confined rooms are still more detrimental; as the air becomes then not only deprived of a part of its oxygene by frequent respiration, but is loaded with animal effluvia as well as with moisture, till it can receive no more; and in consequence, while the cutaneous secretion stands upon the skin in drops for want of exhalation, the lungs are exposed to an insalubrious atmosphere.

I do not deny, that sweating may be so managed as to be serviceable in preventing the return of the cold paroxysm of fevers; like the warm bath, or any other permanent stimulus, as wine, or opium, or the bark. For this purpose it should be continued till past the time of the expected cold fit, supported by moderate doses of wine-whey, with spirit of hartshorn, and moderate degrees of warmth. Its salutary effect, when thus managed, was probably one cause of its having been so much attended to; and the fetid smell, which when profuse is liable to accompany it, gave occasion to the belief, that the supposed material cause of the disease was thus eliminated from the circulation.

When too great external heat is applied, the system is weakened by excess of action, and the torpor which causes the cold paroxysm recurs sooner and more violently. For though some stimuli, as of opium and alcohol, at the same time that they exhaust the sensorial power by promoting increase of fibrous action, may also increase the production or secretion of it in the brain, yet experience teaches us, that the exhaustion far out-balances the increased production, as is evinced by the general debility, which succeeds intoxication.