Being much afflicted with the Night-mare, self-preservation made
me particularly inquisitive about it. In consulting the ancient
Physicians, I found little information concerning it, except dreadful
prognostics; nor could a rational account of it be expected from them,
as they were unacquainted with the circulation of the Blood.
The few Authors who have mention’d it since that glorious discovery,
have also given imperfect accounts of it; which are probably owing to
their not having felt it themselves: for, as it only seizes People in
sleep, continues but a short time, and vanishes as soon as they awake,
the Physician has not an opportunity of making observations of his own,
but must take all from the description of others, who have labour’d
under it. These, I believe, are the reasons that the principal Writers
in Physic have taken so little notice of it. These omissions however
render an enquiry into the nature of this Disease the more interesting
and necessary, and, at the same time, the more difficult.
Under these disadvantages I have ventur’d to communicate the result
of my own observations and reflexions on it; hoping, that a greater
allowance will be made for the errors in this Essay, as it is perhaps
the first that ever appear’d expressly on this subject.
The Night-mare is commonly, and, I believe, justly, attributed to a
stagnation of the Blood; but how this stagnation is produc’d, has not
been explain’d, so far as I know, in a satisfactory manner.
I have carefully collected the observations of the ancient Physicians
concerning the prognostics of this Disorder; not for ostentation, but
to shew at the same time the dangerous consequences and antiquity
of it, in order to make those afflicted with it the more solicitous
to remove its cause in the beginning; for it may be said of the
Night-mare, as of many other Disorders, _Vires acquirit eundo_.
Though the most temperate are sometimes afflicted with this Disease,
yet experience shews that it is generally the offspring of excess:
hence it must have been nearly _coeval_ with Bacchus (though it be
omitted by the _Coan Oracle_;) and Homer probably alludes to its
symptoms in the following lines:
Ως δ’ εν ὀνείρω ὀυ δύναται Φευγοντα διωκειν
Οὔτ’ αρ ὁ δύναται ὑποfευγειν, ὄυθ’ ὁ διωκειν.
Iliad xxii.
I have not introduc’d any thing in this Essay that did not appear
serious or probable. I have therefore omitted an inquiry into the
origin of many odd epithets and quaint names commonly given to this
Disorder; such as _Hag-riding_, _Wizard-pressing_, _Mare-riding_,
_Witch-dancing_, _&c._, nor did I think it requisite to mention
particularly the _curious Charms_ adapted to each superstitious name.
My aim has been to convey my sentiments with as much brevity and
perspicuity as possible. If I have transgress’d this rule, in
occasionally introducing some things known, in order to explain others,
it was to be the more intelligible; I therefore hope, the more learned
will excuse me.
With pleasure I take this opportunity of acknowledging how much
the hints I receiv’d from the instructive lectures of my ingenious
Preceptor Mr. Monro, contributed to this undertaking.