Zoonomia, Vol. I | Page 3

to a person labouring under disease
without thinking, that is, without theorizing; and happy therefore is the
patient, whose physician possesses the best theory.
The words idea, perception, sensation, recollection, suggestion, and
association, are each of them used in this treatise in a more limited
sense than in the writers of metaphysic. The author was in doubt,
whether he should rather have substituted new words instead of them;
but was at length of opinion, that new definitions of words already in
use would be less burthensome to the memory of the reader.
A great part of this work has lain by the writer above twenty years, as
some of his friends can testify: he had hoped by frequent revision to
have made it more worthy the acceptance of the public; this however
his other perpetual occupations have in part prevented, and may
continue to prevent, as long as he may be capable of revising it; he
therefore begs of the candid reader to accept of it in its present state,
and to excuse any inaccuracies of expression, or of conclusion, into
which the intricacy of his subject, the general imperfection of language,
or the frailty he has in common with other men, may have betrayed him;
and from which he has not the vanity to believe this treatise to be
exempt.
* * * * *
ZOONOMIA.
* * * * *

SECT. I.
OF MOTION.
The whole of nature may be supposed to consist of two essences or
substances; one of which may be termed spirit, and the other matter.
The former of these possesses the power to commence or produce
motion, and the latter to receive and communicate it. So that motion,
considered as a cause, immediately precedes every effect; and,
considered as an effect, it immediately succeeds every cause.
The MOTIONS OF MATTER may be divided into two kinds, primary
and secondary. The secondary motions are those, which are given to or
received from other matter in motion. Their laws have been
successfully investigated by philosophers in their treatises on mechanic
powers. These motions are distinguished by this circumstance, that the
velocity multiplied into the quantity of matter of the body acted upon is
equal to the velocity multiplied into the quantity of matter of the acting
body.
The primary motions of matter may be divided into three classes, those
belonging to gravitation, to chemistry, and to life; and each class has its
peculiar laws. Though these three classes include the motions of solid,
liquid, and aerial bodies; there is nevertheless a fourth division of
motions; I mean those of the supposed ethereal fluids of magnetism,
electricity, heat, and light; whose properties are not so well investigated
as to be classed with sufficient accuracy.
_1st._ The gravitating motions include the annual and diurnal rotation
of the earth and planets, the flux and reflux of the ocean, the descent of
heavy bodies, and other phænomena of gravitation. The unparalleled
sagacity of the great NEWTON has deduced the laws of this class of
motions from the simple principle of the general attraction of matter.
These motions are distinguished by their tendency to or from the
centers of the sun or planets.
_2d._ The chemical class of motions includes all the various
appearances of chemistry. Many of the facts, which belong to these

branches of science, are nicely ascertained, and elegantly classed; but
their laws have not yet been developed from such simple principles as
those above-mentioned; though it is probable, that they depend on the
specific attractions belonging to the particles of bodies, or to the
difference of the quantity of attraction belonging to the sides and angles
of those particles. The chemical motions are distinguished by their
being generally attended with an evident decomposition or new
combination of the active materials.
_3d._ The third class includes all the motions of the animal and
vegetable world; as well those of the vessels, which circulate their
juices, and of the muscles, which perform their locomotion, as those of
the organs of sense, which constitute their ideas.
This last class of motion is the subject of the following pages; which,
though conscious of their many imperfections, I hope may give some
pleasure to the patient reader, and contribute something to the
knowledge and to the cure of diseases.
* * * * *
SECT. II.
EXPLANATIONS AND DEFINITIONS.
I. _Outline of the animal economy._--II. 1. _Of the sensorium._ 2. _Of
the brain and nervous medulla._ 3. _A nerve._ 4. _A muscular fibre._ 5.
_The immediate organs of sense._ 6. _The external organs of sense._ 7.
_An idea or sensual motion._ 8. _Perception._ 9. _Sensation._ 10.
_Recollection and suggestion._ 11. _Habit, causation, association,
catenation._ 12. _Reflex ideas._ 13. _Stimulus defined._
* * * * *
As some explanations and definitions will be necessary in