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Transcriber's note

A few typographical errors have been corrected: they are
listed at the end of the text.





ZOONOMIA;

OR,

THE LAWS

OF

ORGANIC LIFE.

VOL. II.

_By ERASMUS DARWIN, M.D. F.R.S._

AUTHOR OF THE BOTANIC GARDEN.



  Principio coelum, ac terras, camposque liquentes,
  Lucentemque globum lunae, titaniaque astra,
  Spiritus intus alit, totamque infusa per artus
  Mens agitat molem, et magno se corpore miscet.--VIRG. Aen. vi.

  Earth, on whose lap a thousand nations tread,
  And Ocean, brooding his prolific bed,
  Night's changeful orb, blue pole, and silvery zones,
  Where other worlds encircle other suns,
  One Mind inhabits, one diffusive Soul
  Wields the large limbs, and mingles with the whole.







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.

       *       *       *       *       *

    Haec, ut potero, explicabo; nec tamen, quasi Pythius Apollo, certa ut
    sint et fixa, quae dixero; sed ut Homunculus unus e multis probabiliora
    conjectura 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 causae eorum
proximae, qualiscunque sit, revera 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 diarrhoea,
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.