_An account of the Symptoms._
Having now discover’d what appears, to me, to be the immediate cause of
the Night-mare, viz. the pressure of the Heart on the left or inferior
Auricle and Pulmonary Veins, which stops the motion of the Blood
through the Lungs, and occasions a general stagnation; let us examine
how that hypothesis will account for the several Phænomena or Symptoms,
mention’d formerly in the description of this Disease.
The first Symptoms that occur in that catalogue, are frightful Dreams,
which generally are the forerunners of this Disorder. “In hoc genere
(Somniorum) est Εφιαλτης quem publica persuasio quiescentes opinatur
invadere, ac sentientes pondere suo gravare[12].”
I shall not here undertake to solve that Phænomenon, which has so long
puzzled the Metaphysicians, nor pretend to account for all kinds of
dreams in a mechanical manner.
However, every one knows that the harmony and connection between the
Body and the Mind are so establish’d and constituted, while they are
united, that the Diseases of the one always affect the other in a
very sensible manner; and experience daily demonstrates, that violent
passions of the mind produce Fevers, Fainting Fits, and other severe
effects on the Body; e. contra, violent shocks of the Body, acute
Diseases, &c. frequently disturb, and raise strange commotions in the
Mind, or at least excite extravagant, wild ideas in it. Accordingly we
find, that the most eminent Physicians have not scrupl’d to assert,
that these effects are often owing to Obstructions and Inflammations
of the Membranes of the Brain. If so, may not the violent distentions
of the Vessels of the Brain (which always precedes and attends a fit
of the Night-mare) make such strong impressions on the origin of the
Nerves, or Sensorium Commune, as to occasion hideous associations of
ideas, and form frightful spectres in the imagination? Are not these
monstrous dreams intended as a stimulus to rouse the sentient principle
in us, that we might alter the position of the Body, and by that means
avoid the approaching danger? Is not the horizontal posture of the
Body, which produces a Plethora in the Vessels of the Brain, and many
odd sensations, the most general cause of dreams? Do they ever dream,
who sleep in an erect position? Are not the luxurious and the plethoric
most subject to disagreeable dreams? Is not the motion and titillation
of the Animalculæ in Semine Masculino, the cause of the agreeable
dreams which attend nocturnal emissions? Have females such emissions
in sleep? Does not perfect sleep consist in a total suspension of the
operations of the Mind? May not dreaming, in general, be consider’d
as a Disorder of the Body, and justly attributed to some cause, which
stimulates the Sensorium Commune, and prevents perfect rest? Do people
that sleep after much fatigue, ever dream?
The vast oppression on the Breast, and immobility of the Body, which
are always felt in this Disorder, probably arise from the quantity
of Blood collected in the Lungs, Vena Cava, right Ventricle, and
Auricle of the Heart; nor does the Mind appear to be mistaken in this
case, as some have imagined; for it seems the same with regard to
the Mind, whether the real action of the Muscles be constrain’d by a
superior external force, or the influence of it over these Muscles be
hinder’d by an internal cause. In a fit of the Night-mare, the Mind,
conscious of the dangerous situation of the Body, in vain endeavours
to alter it, because its power over the Voluntary Muscles is some way
suspended, by the obstruction of the Blood; yet the Mind may exert
itself as much as if it strove to remove the greatest obstacle. In this
case the Mind generally ascribes the immobility of the Body to some
great weight laid on the Breast; whereas the cause is really internal:
and people judge of the greatness of the oppression, according to the
efforts nature makes to overcome the obstruction of the Blood in the
Lungs.
Besides, in heavy or profound sleep, the voluntary motions are
generally stop’d. Hence, when people awake suddenly, they are for some
time Paralytic, before the Animal Spirits obey the commands of the
Mind, and actuate the Muscles in the usual manner.
The indistinct Voice is probably owing to the same cause; for the
Muscles of the Tongue and Larynx, which form distinct sounds, are
of the voluntary class, which, as was said before, are generally
suspended in sleep.
The collapsing of the Lungs, which are, at this time, overloaded with
Blood, will exclude the air, that necessary medium of sounds, and sole
vehicle of voice.
Heavy sighs and groans are the emphatic expressions of nature in
distress, and generally arise from some obstruction in the Lungs; but
in a fit of the Night-mare there appears a great accumulation of Blood
in the vessels of that part, whence these Symptoms are easily accounted
for. It may be observ’d of sighing in general, that when the attention
of the Mind is deeply engag’d to any particular object or sensation,
and either neglects or is restrain’d from exerting its influence over
the organs of respiration, the Blood is stop’d in the Lungs, so that
it becomes necessary to draw in a large Chestful of air, in order to
give the Blood a free passage from the right Ventricle of the Heart to
the left. Hence Melancholy persons, profound Mathematicians, and fond
pining Lovers, are most subject to that affection. Such people are also
very liable to many Hypochondriac and Chronic Diseases; which often
proceed from a defective respiration, or a too slow motion of the Blood
through those parts which are agitated by the alternate dilatation
and contraction of the Thorax. Hence the Liver and Spleen and the
Lungs themselves must suffer most when the attention of the Mind is
engag’d by some Disease of its own, and it becomes less sensible of the
Disorders of the Body. Hence people in Grief, &c. labour under a double
Disease, which, on account of the anxiety, weight, and oppression that
is felt from the Blood stagnating about the Heart, is commonly termed
Heart-breaking.
An Uneasiness or Anxiety, and Palpitation of the Heart, are the last
Symptoms that are commonly felt of the Night-mare, which proceed from
the cause lately mention’d; as ’tis then necessary that the Heart
should contract itself more frequently, in order to discharge the Blood
collected in the Vena Cava, the right Sinus Venosus, and Auricle,
during the fit.
Having done what I propos’d in this Chapter, and given the best account
that I know of the Symptoms, I should now proceed to the Prognostics
and method of Cure; but, as I have shewn how the vital motions are
stop’d, and a general stagnation of the Blood is produc’d, it is also
incumbent on me to explain how the motion of that vital stream is
renew’d by the efforts of nature alone; otherwise it might be objected,
that, according to my theory, unless where art interpos’d, every fit of
the Night-mare would be mortal.