an inexpressible degree, as above described, before the convulsions have
supervened; and which were preceded by screaming, and grinning; in others,
as in the common epilepsy, the convulsion has immediately succeeded the
commencement of the disagreeable sensations; and as a stupor frequently
succeeds the convulsions, they only seemed to remember that a pain at the
stomach preceded the fit, or some other uneasy feel; or more frequently
retained no memory at all of the immediate cause of the paroxysm. But even
in this kind of epilepsy, where the patient does not recollect any
preceding pain, the paroxysms generally are preceded by a quivering motion
of the under jaw, with a biting of the tongue; the teeth afterwards become
pressed together with vehemence, and the eyes are then convulsed, before
the commencement of the universal convulsion; which are all efforts to
relieve pain.
The reason why these convulsive motions are alternately exerted and
remitted was mentioned above, and in Sect. XII. 1. 3. when the exertions
are such as give a temporary relief to the pain, which excites them, they
cease for a time, till the pain is again perceived; and then new exertions
are produced for its relief. We see daily examples of this in the loud
reiterated laughter of some people; the pleasureable sensation, which
excites this laughter, arises for a time so high as to change its name and
become painful: the convulsive motions of the respiratory muscles relieve
the pain for a time; we are, however, unwilling to lose the pleasure, and
presently put a stop to this exertion, and immediately the pleasure recurs,
and again as instantly rises into pain. All of us have felt the pain of
immoderate laughter; children have been tickled into convulsions of the
whole body; and others have died in the act of laughing; probably from a
paralysis succeeding the long continued actions of the muscles of
respiration.
Hence we learn the reason, why children, who are so easily excited to laugh
by the tickling of other people's fingers, cannot tickle themselves into
laughter. The exertion of their hands in the endeavour to tickle themselves
prevents the necessity of any exertion of the respiratory muscles to
relieve the excess of pleasurable affection. See Sect. XVII. 3. 5.
Chrysippus is recorded to have died laughing, when an ass was invited to
sup with him. The same is related of one of the popes, who, when he was
ill, saw a tame monkey at his bedside put on the holy thiara. Hall. Phys.
T. III. p. 306.
There are instances of epilepsy being produced by laughing recorded by Van
Swieten, T. III. 402 and 308. And it is well known, that many people have
died instantaneously from the painful excess of joy, which probably might
have been prevented by the exertions of laughter.
Every combination of ideas, which we attend to, occasions pain or pleasure;
those which occasion pleasure, furnish either social or selfish pleasure,
either malicious or friendly, or lascivious, or sublime pleasure; that is,
they give us pleasure mixed with other emotions, or they give us unmixed
pleasure, without occasioning any other emotions or exertions at the same
time. This unmixed pleasure, if it be great, becomes painful, like all
other animal motions from stimuli of every kind; and if no other exertions
are occasioned at the same time, we use the exertion of laughter to relieve
this pain. Hence laughter is occasioned by such wit as excites simple
pleasure without any other emotion, such as pity, love, reverence. For
sublime ideas are mixed with admiration, beautiful ones with love, new ones
with surprise; and these exertions of our ideas prevent the action of
laughter from being necessary to relieve the painful pleasure above
described. Whence laughable wit consists of frivolous ideas, without
connections of any consequence, such as puns on words, or on phrases,
incongruous junctions of ideas; on which account laughter is so frequent in
children.
Unmixed pleasure less than that, which causes laughter, causes sleep, as in
singing children to sleep, or in slight intoxication from wine or food. See
Sect. XVIII. 12.
5. If the pains, or disagreeable sensations, above described do not obtain
a temporary relief from these convulsive exertions of the muscles, those
convulsive exertions continue without remission, and one kind of catalepsy
is produced. Thus when a nerve or tendon produces great pain by its being
inflamed or wounded, the patient sets his teeth firmly together, and grins
violently, to diminish the pain; and if the pain is not relieved by this
exertion, no relaxation of the maxillary muscles takes place, as in the
convulsions above described, but the jaws remain firmly fixed together.
This locked jaw is the most frequent instance of cataleptic spasm, because
we are more inclined to exert the muscles subservient to mastication from
their early obedience to violent efforts of volition.
But in the case related in Sect. XIX. on Reverie, the cataleptic lady had
pain in her upper teeth; and pressing one of her hands vehemently against
her cheek-bone to diminish this pain, it remained in that attitude for
about half an hour twice a day, till the painful paroxysm was over.
I have this very day seen a young lady in this disease, (with which she has
frequently been afflicted,) she began to-day with violent pain shooting
from one side of the forehead to the occiput, and after various struggles
lay on the bed with her fingers and wrists bent and stiff for about two
hours; in other respects she seemed in a syncope with a natural pulse. She
then had intervals of pain and of spasm, and took three grains of opium
every hour till she had taken nine grains, before the pains and spasm
ceased.
There is, however, another species of fixed spasm, which differs from the
former, as the pain exists in the contracted muscle, and would seem rather
to be the consequence than the cause of the contraction, as in the cramp in
the calf of the leg, and in many other parts of the body.
In these spasms it should seem, that the muscle itself is first thrown into
contraction by some disagreeable sensation, as of cold; and that then the
violent pain is produced by the great contraction of the muscular fibres
extending its own tendons, which are said to be sensible to extension only;
and is further explained in Sect. XVIII. 15.
6. Many instances have been given in this work, where after violent motions
excited by irritation, the organ has become quiescent to less, and even to
the great irritation, which induced it into violent motion; as after
looking long at the sun or any bright colour, they cease to be seen; and
after removing from bright day-light into a gloomy room, the eye cannot at
first perceive the objects, which stimulate it less. Similar to this is the
syncope, which succeeds after the violent exertions of our voluntary
motions, as after epileptic fits, for the power of volition acts in this
case as the stimulus in the other. This syncope is a temporary palsy, or
apoplexy, which ceases after a time, the muscles recovering their power of
being excited into action by the efforts of volition; as the eye in the
circumstance above mentioned recovers in a little time its power of seeing
objects in a gloomy room; which were invisible immediately after coming out
of a stronger light. This is owing to an accumulation of sensorial power
during the inaction of those fibres, which were before accustomed to
perpetual exertions, as explained in Sect. XII. 7. 1. A slighter degree of
this disease is experienced by every one after great fatigue, when the
muscles gain such inability to further action, that we are obliged to rest
them for a while, or to summon a greater power of volition to continue
their motions.
In all the syncopes, which I have seen induced after convulsive fits, the
pulse has continued natural, though the organs of sense, as well as the
locomotive muscles, have ceased to perform their functions; for it is
necessary for the perception of objects, that the external organs of sense
should be properly excited by the voluntary power, as the eye-lids must be
open, and perhaps the muscles of the eye put into action to distend, and
thence give greater pellucidity to the cornea, which in syncope, as in
death, appears flat and less transparent.
The tympanum of the ear also seems to require a voluntary exertion of its
muscles, to gain its due tension, and it is probable the other external
organs of sense require a similar voluntary exertion to adapt them to the
distinct perception of objects. Hence in syncope as in sleep, as the power
of volition is suspended, no external objects are perceived. See Sect.
XVIII. 5. During the time which the patient lies in a fainting fit, the
spirit of animation becomes accumulated; and hence the muscles in a while
become irritable by their usual stimulation, and the fainting fit ceases.
See Sect. XII. 7. 1.
7. If the exertion of the voluntary motions has been still more energetic,
the quiescence, which succeeds, is so complete, that they cannot again be
excited into action by the efforts of the will. In this manner the palsy,
and apoplexy (which is an universal palsy) are frequently produced after
convulsions, or other violent exertions; of this I shall add a few
instances.
Platernus mentions some, who have died apoplectic from violent exertions in
dancing; and Dr. Mead, in his Essay on Poisons, records a patient in the
hydrophobia, who at one effort broke the cords which bound him, and at the
same instant expired. And it is probable, that those, who have expired from
immoderate laughter, have died from this paralysis consequent to violent
exertion. Mrs. Scott of Stafford was walking in her garden in perfect
health with her neighbour Mrs. ----; the latter accidentally fell into a
muddy rivulet, and tried in vain to disengage herself by the assistance of
Mrs. Scott's hand. Mrs. Scott exerted her utmost power for many minutes,
first to assist her friend, and next to prevent herself from being pulled
into the morass, as her distressed companion would not disengage her hand.
After other assistance was procured by their united screams, Mrs. Scott
walked to a chair about twenty yards from the brook, and was seized with an
apoplectic stroke: which continued many days, and terminated in a total
loss of her right arm, and her speech; neither of which she ever after
perfectly recovered.
It is said, that many people in Holland have died after skating too long or
too violently on their frozen canals; it is probable the death of these,
and of others, who have died suddenly in swimming, has been owing to this
great quiescence or paralysis; which has succeeded very violent exertions,
added to the concomitant cold, which has had greater effect after the
sufferers had been heated and exhausted by previous exercise.
I remember a young man of the name of Nairne at Cambridge, who walking on
the edge of a barge fell into the river. His cousin and fellow-student of
the same name, knowing the other could not swim, plunged into the water
after him, caught him by his clothes, and approaching the bank by a
vehement exertion propelled him safe to the land, but that instant, seized,
as was supposed, by the cramp, or paralysis, sunk to rise no more. The
reason why the cramp of the muscles, which compose the calf of the leg, is
so liable to affect swimmers, is, because these muscles have very weak
antagonists, and are in walking generally elongated again after their
contraction by the weight of the body on the ball of the toe, which is very
much greater than the resistance of the water in swimming. See Section
XVIII. 15.
It does not follow that every apoplectic or paralytic attack is immediately
preceded by vehement exertion; the quiescence, which succeeds exertion, and
which is not so great as to be termed paralysis, frequently recurs
afterwards at certain periods; and by other causes of quiescence, occurring
with those periods, as was explained in treating of the paroxysms of
intermitting fevers; the quiescence at length, becomes so great as to be
incapable of again being removed by the efforts of volition, and complete
paralysis is formed. See Section XXXII. 3. 2.
Many of the paralytic patients, whom I have seen, have evidently had
diseased livers from the too frequent potation of spirituous liquors; some
of them have had the gutta rosea on their faces and breasts; which has in
some degree receded either spontaneously, or by the use of external
remedies, and the paralytic stroke has succeeded; and as in several
persons, who have drank much vinous spirits, I have observed epileptic fits
to commence at about forty or fifty years of age, without any hereditary
taint, from the stimulus, as I believed, of a diseased liver; I was induced
to ascribe many paralytic cases to the same source; which were not
evidently the effect of age, or of unacquired debility. And the account
given before of dropsies, which very frequently are owing to a paralysis of
the absorbent system, and are generally attendant on free drinkers of
spirituous liquors, confirmed me in this opinion.
The disagreeable irritation of a diseased liver produces exertions and
consequent quiescence; these by the accidental concurrence of other causes
of quiescence, as cold, solar or lunar periods, inanition, the want of
their usual portion of spirit of wine, at length produces paralysis.
This is further confirmed by observing, that the muscles, we most
frequently, or most powerfully exert, are most liable to palsy; as those of
the voice and of articulation, and of those paralytics which I have seen, a
much greater proportion have lost the use of their right arm; which is so
much more generally exerted than the left.
I cannot dismiss this subject without observing, that after a paralytic
stroke, if the vital powers are not much injured, that the patient has all
the movements of the affected limb to learn over again, just as in early
infancy; the limb is first moved by the irritation of its muscles, as in
stretching, (of which a case was related in Section VII. 1. 3.) or by the
electric concussion; afterwards it becomes obedient to sensation, as in
violent danger or fear; and lastly, the muscles become again associated
with volition, and gradually acquire their usual habits of acting together.
Another phænomenon in palsies is, that when the limbs of one side are
disabled, those of the other are in perpetual motion. This can only be
explained from conceiving that the power of motion, whatever it is, or
wherever it resides, and which is capable of being exhausted by fatigue,
and accumulated in rest, is now less expended, whilst one half of the body
is capable of receiving its usual proportion of it, and is hence derived
with greater ease or in greater abundance into the limbs, which remain
unaffected.
II. 1. The excess or defect of voluntary exertion produces similar effects
upon the sensual motions, or ideas of the mind, as those already mentioned
upon the muscular fibres. Thus when any violent pain, arising from the
defect of some peculiar stimulus, exists either in the muscular or sensual
systems of fibres, and which cannot be removed by acquiring the defective
stimulus; as in some constitutions convulsions of the muscles are produced
to procure a temporary relief, so in other constitutions vehement voluntary
exertions of the ideas of the mind are produced for the same purpose; for
during this exertion, like that of the muscles, the pain either vanishes or
is diminished: this violent exertion constitutes madness; and in many cases
I have seen the madness take place, and the convulsions cease, and
reciprocally the madness cease, and the convulsions supervene. See Section
III. 5. 8.
2. Madness is distinguishable from delirium, as in the latter the patient
knows not the place where he resides, nor the persons of his friends or
attendants, nor is conscious of any external objects, except when spoken to
with a louder voice, or stimulated with unusual force, and even then he
soon relapses into a state of inattention to every thing about him. Whilst
in the former he is perfectly sensible to every thing external, but has the
voluntary powers of his mind intensely exerted on some particular object of
his desire or aversion, he harbours in his thoughts a suspicion of all
mankind, lest they should counteract his designs; and while he keeps his
intentions, and the motives of his actions profoundly secret; he is
perpetually studying the means of acquiring the object of his wish, or of
preventing or revenging the injuries he suspects.
3. A late French philosopher, Mr. Helvetius, has deduced almost all our
actions from this principle of their relieving us from the ennui or tædium
vitæ; and true it is, that our desires or aversions are the motives of all
our voluntary actions; and human nature seems to excel other animals in the
more facil use of this voluntary power, and on that account is more liable
to insanity than other animals. But in mania this violent exertion of
volition is expended on mistaken objects, and would not be relieved, though
we were to gain or escape the objects, that excite it. Thus I have seen two
instances of madmen, who conceived that they had the itch, and several have
believed they had the venereal infection, without in reality having a
symptom of either of them. They have been perpetually thinking upon this
subject, and some of them were in vain salivated with design of convincing
them to the contrary.
4. In the minds of mad people those volitions alone exist, which are
unmixed with sensation; immoderate suspicion is generally the first
symptom, and want of shame, and want of delicacy about cleanliness.
Suspicion is a voluntary exertion of the mind arising from the pain of
fear, which it is exerted to relieve: shame is the name of a peculiar
disagreeable sensation, see Fable of the Bees, and delicacy about
cleanliness arises from another disagreeable sensation. And therefore are
not found in the minds of maniacs, which are employed solely in voluntary
exertions. Hence the most modest women in this disease walk naked amongst
men without any kind of concern, use obscene discourse, and have no
delicacy about their natural evacuations.
5. Nor are maniacal people more attentive to their natural appetites, or to
the irritations which surround them, except as far as may respect their
suspicions or designs; for the violent and perpetual exertions of their
voluntary powers of mind prevents their perception of almost every other
object, either of irritation or of sensation. Hence it is that they bear
cold, hunger, and fatigue, with much greater pertinacity than in their
sober hours, and are less injured by them in respect to their general
health. Thus it is asserted by historians, that Charles the Twelfth of
Sweden slept on the snow, wrapped only in his cloak, at the siege of
Frederickstad, and bore extremes of cold and hunger, and fatigue, under
which numbers of his soldiers perished; because the king was insane with
ambition, but the soldier had no such powerful stimulus to preserve his
system from debility and death.
6. Besides the insanities arising from exertions in consequence of pain,
there is also a pleasurable insanity, as well as a pleasurable delirium; as
the insanity of personal vanity, and that of religious fanaticism. When
agreeable ideas excite into motion the sensorial power of sensation, and
this again causes other trains of agreeable ideas, a constant stream of
pleasurable ideas succeeds, and produces pleasurable delirium. So when the
sensorial power of volition excites agreeable ideas, and the pleasure thus
produced excites more volition in its turn, a constant flow of agreeable
voluntary ideas succeeds; which when thus exerted in the extreme
constitutes insanity.
Thus when our muscular actions are excited by our sensations of pleasure,
it is termed play; when they are excited by our volition, it is termed
work; and the former of these is attended with less fatigue, because the
muscular actions in play produce in their turn more pleasurable sensation;
which again has the property of producing more muscular action. An
agreeable instance of this I saw this morning. A little boy, who was tired
with walking, begged of his papa to carry him. "Here," says the reverend
doctor, "ride upon my gold-headed cane;" and the pleased child, putting it
between his legs, gallopped away with delight, and complained no more of
his fatigue. Here the aid of another sensorial power, that of pleasurable
sensation, superadded vigour to the exertion of exhausted volition. Which
could otherwise only have been excited by additional pain, as by the lash
of slavery. On this account where the whole sensorial power has been
exerted on the contemplation of the promised joys of heaven, the saints of
all persecuted religions have borne the tortures of martyrdom with
otherwise unaccountable firmness.
7. There are some diseases, which obtain at least a temporary relief from
the exertions of insanity; many instances of dropsies being thus for a time
cured are recorded. An elderly woman labouring with ascites I twice saw
relieved for some weeks by insanity, the dropsy ceased for several weeks,
and recurred again alternating with the insanity. A man afflicted with
difficult respiration on lying down, with very irregular pulse, and
oedematous legs, whom I saw this day, has for above a week been much
relieved in respect to all those symptoms by the accession of insanity,
which is shewn by inordinate suspicion, and great anger.
In cases of common temporary anger the increased action of the arterial
system is seen by the red skin, and increased pulse, with the immediate
increase of muscular activity. A friend of mine, when he was painfully
fatigued by riding on horseback, was accustomed to call up ideas into his
mind, which used to excite his anger or indignation, and thus for a time at
least relieved the pain of fatigue. By this temporary insanity, the effect
of the voluntary power upon the whole of his system was increased; as in
the cases of dropsy above mentioned, it would appear, that the increased
action of the voluntary faculty of the sensorium affected the absorbent
system, as well as the secerning one.
8. In respect to relieving inflammatory pains, and removing fever, I have
seen many instances, as mentioned in Sect. XII. 2. 4. One lady, whom I
attended, had twice at some years interval a locked jaw, which relieved a
pain on her sternum with peripneumony. Two other ladies I saw, who towards
the end of violent peripneumony, in which they frequently lost blood, were
at length cured by insanity supervening. In the former the increased
voluntary exertion of the muscles of the jaw, in the latter that of the
organs of sense, removed the disease; that is, the disagreeable sensation,
which had produced the inflammation, now excited the voluntary power, and
these new voluntary exertions employed or expended the superabundant
sensorial power, which had previously been exerted on the arterial system,
and caused inflammation.
Another case, which I think worth relating, was of a young man about
twenty; he had laboured under an irritative fever with debility for three
or four weeks, with very quick and very feeble pulse, and other usual
symptoms of that species of typhus, but at this time complained much and
frequently of pain of his legs and feet. When those who attended him were
nearly in despair of his recovery, I observed with pleasure an insanity of
mind supervene: which was totally different from delirium, as he knew his
friends, calling them by their names, and the room in which he lay, but
became violently suspicious of his attendants, and calumniated with
vehement oaths his tender mother, who sat weeping by his bed. On this his
pulse became slower and firmer, but the quickness did not for some time
intirely cease, and he gradually recovered. In this case the introduction
of an increased quantity of the power of volition gave vigour to those
movements of the system, which are generally only actuated by the power of
irritation, and of association.
Another case I recollect of a young man, about twenty-five, who had the
scarlet-fever, with very quick pulse, and an universal eruption on his
skin, and was not without reason esteemed to be in great danger of his
life. After a few days an insanity supervened, which his friends mistook
for delirium, and he gradually recovered, and the cuticle peeled off. From
these and a few other cases I have always esteemed insanity to be a
favourable sign in fevers, and have cautiously distinguished it from
delirium.
III. Another mode of mental exertion to relieve pain, is by producing a
train of ideas not only by the efforts of volition, as in insanity; but by
those of sensation likewise, as in delirium and sleep. This mental effort
is termed reverie, or somnambulation, and is described more at large in
Sect. XIX. on that subject. But I shall here relate another case of that
wonderful disease, which fell yesterday under my eye, and to which I have
seen many analogous alienations of mind, though not exactly similar in all
circumstances. But as all of them either began or terminated with pain or
convulsion, there can be no doubt but that they are of epileptic origin,
and constitute another mode of mental exertion to relieve some painful
sensation.
1. Master A. about nine years old, had been seized at seven every morning
for ten days with uncommon fits, and had had slight returns in the
afternoon. They were supposed to originate from worms, and had been in vain
attempted to be removed by vermifuge purges. As his fit was expected at
seven yesterday morning, I saw him before that hour; he was asleep, seemed
free from pain, and his pulse natural. About seven he began to complain of
pain about his navel, or more to the left side, and in a few minutes had
exertions of his arms and legs like swimming. He then for half an hour
hunted a pack of hounds; as appeared by his hallooing, and calling the dogs
by their names, and discoursing with the attendants of the chase,
describing exactly a day of hunting, which (I was informed) he had
witnessed a year before, going through all the most minute circumstances of
it; calling to people, who were then present, and lamenting the absence of
others, who were then also absent. After this scene he imitated, as he lay
in bed, some of the plays of boys, as swimming and jumping. He then sung an
English and then an Italian song; part of which with his eyes open, and
part with them closed, but could not be awakened or excited by any
violence, which it was proper to use.
After about an hour he came suddenly to himself with apparent surprise, and
seemed quite ignorant of any part of what had passed, and after being
apparently well for half an hour, he suddenly fell into a great stupor,
with slower pulse than natural, and a slow moaning respiration, in which he
continued about another half hour, and then recovered.
The sequel of this disease was favourable; he was directed one grain of
opium at six every morning, and then to rise out of bed; at half past six
he was directed fifteen drops of laudanum in a glass of wine and water. The
first day the paroxysm became shorter, and less violent. The dose of opium
was increased to one-half more, and in three or four days the fits left
him. The bark and filings of iron were also exhibited twice a day; and I
believe the complaint returned no more.
2. In this paroxysm it must be observed, that he began with pain, and ended
with stupor, in both circumstances resembling a fit of epilepsy. And that
therefore the exertions both of mind and body, both the voluntary ones, and
those immediately excited by pleasurable sensation, were exertions to
relieve pain.
The hunting scene appeared to be rather an act of memory than of
imagination, and was therefore rather a voluntary exertion, though attended
with the pleasurable eagerness, which was the consequence of those ideas
recalled by recollection, and not the cause of them.
These ideas thus voluntarily recollected were succeeded by sensations of
pleasure, though his senses were unaffected by the stimuli of visible or
audible objects; or so weakly excited by them as not to produce sensation
or attention. And the pleasure thus excited by volition produced other
ideas and other motions in consequence of the sensorial power of sensation.
Whence the mixed catenations of voluntary and sensitive ideas and muscular
motions in reverie; which, like every other kind of vehement exertion,
contribute to relieve pain, by expending a large quantity of sensorial
power.
Those fits generally commence during sleep, from whence I suppose they have
been thought to have some connection with sleep, and have thence been
termed Somnambulism; but their commencement during sleep is owing to our
increased excitability by internal sensations at that time, as explained in
Sect. XVIII. 14. and 15., and not to any similitude between reverie and
sleep.
3. I was once concerned for a very elegant and ingenious young lady, who
had a reverie on alternate days, which continued nearly the whole day; and
as in her days of disease she took up the same kind of ideas, which she had
conversed about on the alternate day before, and could recollect nothing of
them on her well-day; she appeared to her friends to possess two minds.
This case also was of epileptic kind, and was cured, with some relapses, by
opium administered before the commencement of the paroxysm.
4. Whence it appears, that the methods of relieving inflammatory pains, is
by removing all stimulus, as by venesection, cool air, mucilaginous diet,
aqueous potation, silence, darkness.
The methods of relieving pains from defect of stimulus is by supplying the
peculiar stimulus required, as of food, or warmth.
And the general method of relieving pain is by exciting into action some
great part of the system for the purpose of expending a part of the
sensorial power. This is done either by exertion of the voluntary ideas and
muscles, as in insanity and convulsion; or by exerting both voluntary and
sensitive motions, as in reverie; or by exciting the irritative motions by
wine or opium internally, and by the warm bath or blisters externally; or
lastly, by exciting the sensitive ideas by good news, affecting stories, or
agreeable passions.
* * * * *
SECT. XXXV.
DISEASES OF ASSOCIATION.
I. 1. _Sympathy or consent of parts. Primary and secondary parts of an
associated train of motions reciprocally affect each other. Parts of
irritative trains of motion affect each other in four ways. Sympathies
of the skin and stomach. Flushing of the face after a meal. Eruption of
the small-pox on the face. Chilness after a meal._ 2. _Vertigo from
intoxication._ 3. _Absorption from the lungs and pericardium by
emetics. In vomiting the actions of the stomach are decreased, not
increased. Digestion strengthened after an emetic. Vomiting from
deficiency of sensorial power._ 4. _Dyspnoea from cold bathing. Slow
pulse from digitalis. Death from gout in the stomach._ II. 1. _Primary
and secondary parts of sensitive associations affect each other. Pain
from gall-stone, from urinary stone, Hemicrania. Painful epilepsy._ 2.
_Gout and red face from inflamed liver. Shingles from inflamed kidney._
3. _Coryza from cold applied to the feet. Pleurisy. Hepatitis._ 4.
_Pain of shoulders from inflamed liver._ III. _Diseases from the
associations of ideas._
I. 1. Many synchronous and successive motions of our muscular fibres, and
of our organs of sense, or ideas, become associated so as to form
indissoluble tribes or trains of action, as shewn in Section X. on
Associate Motions. Some constitutions more easily establish these
associations, whether by voluntary, sensitive, or irritative repetitions,
and some more easily lose them again, as shewn in Section XXXI. on
Temperaments.
When the beginning of such a train of actions becomes by any means
disordered, the succeeding part is liable to become disturbed in
consequence, and this is commonly termed sympathy or consent of parts by
the writers of medicine. For the more clear understanding of these
sympathies we must consider a tribe or train of actions as divided into two
parts, and call one of them the primary or original motions, and the other
the secondary or sympathetic ones.
The primary and secondary parts of a train of irritative actions may
reciprocally affect each other in four different manners. 1. They may both
be exerted with greater energy than natural. 2. The former may act with
greater, and the latter with less energy. 3. The former may act with less,
and the latter with greater energy. 4. They may both act with less energy
than natural. I shall now give an example of each kind of these modes of
action, and endeavour to shew, that though the primary and secondary parts
of these trains or tribes of motion are connected by irritative
association, or their previous habits of acting together, as described in
Sect. XX. on Vertigo. Yet that their acting with similar or dissimilar
degrees of energy, depends on the greater or less quantity of sensorial
power, which the primary part of the train expends in its exertions.
The actions of the stomach constitute so important a part of the
associations of both irritative and sensitive motions, that it is said to
sympathize with almost every part of the body; the first example, which I
shall adduce to shew that both the primary and secondary parts of a train
of irritative associations of motion act with increased energy, is taken
from the consent of the skin with this organ. When the action of the fibres
of the stomach is increased, as by the stimulus of a full meal, the
exertions of the cutaneous arteries of the face become increased by their
irritative associations with those of the stomach, and a glow or flushing
of the face succeeds. For the small vessels of the skin of the face having
been more accustomed to the varieties of action, from their frequent
exposure to various degrees of cold and heat become more easily excited
into increased action, than those of the covered parts of our bodies, and
thus act with more energy from their irritative or sensitive associations
with the stomach. On this account in small-pox the eruption in consequence
of the previous affection of the stomach breaks out a day sooner on the
face than on the hands, and two days sooner than on the trunk, and recedes
in similar times after maturation.
But secondly, in weaker constitutions, that is, in those who possess less
sensorial power, so much of it is expended in the increased actions of the
fibres of the stomach excited by the stimulus of a meal, that a sense of
chilness succeeds instead of the universal glow above mentioned; and thus
the secondary part of the associated train of motions is diminished in
energy, in consequence of the increased activity of the primary part of it.
2. Another instance of a similar kind, where the secondary part of the
train acts with less energy in consequence of the greater exertions of the
primary part, is the vertigo attending intoxication; in this circumstance
so much sensorial power is expended on the stomach, and on its nearest or
more strongly associated motions, as those of the subcutaneous vessels, and
probably of the membranes of some internal viscera, that the irritative
motions of the retina become imperfectly exerted from deficiency of
sensorial power, as explained in Sect. XX. and XXI. 3. on Vertigo and on
Drunkenness, and hence the staggering inebriate cannot completely balance
himself by such indistinct vision.
3. An instance of the third circumstance, where the primary part of a train
of irritative motions acts with less, and the secondary part with greater
energy, may be observed by making the following experiment. If a person
lies with his arms and shoulders out of bed, till they become cold, a
temporary coryza or catarrh is produced; so that the passage of the
nostrils becomes totally obstructed; at least this happens to many people;
and then on covering the arms and shoulders, till they become warm, the
passage of the nostrils ceases again to be obstructed, and a quantity of
mucus is discharged from them. In this case the quiescence of the vessels
of the skin of the arms and shoulders, occasioned by exposure to cold air,
produces by irritative association an increased action of the vessels of
the membrane of the nostrils; and the accumulation of sensorial power
during the torpor of the arms and shoulders is thus expended in producing a
temporary coryza or catarrh.
Another instance may be adduced from the sympathy or consent of the motions
of the stomach with other more distant links of the very extensive tribes
or trains of irritative motions associated with them, described in Sect.
XX. on Vertigo. When the actions of the fibres of the stomach are
diminished or inverted, the actions of the absorbent vessels, which take up
the mucus from the lungs, pericardium, and other cells of the body, become
increased, and absorb the fluids accumulated in them with greater avidity,
as appears from the exhibition of foxglove, antimony, or other emetics in
cases of anasarca, attended with unequal pulse and difficult respiration.
That the act of nausea and vomiting is a decreased exertion of the fibres
of the stomach may be thus deduced; when an emetic medicine is
administered, it produces the pain of sickness, as a disagreeable taste in
the mouth produces the pain of nausea; these pains, like that of hunger, or
of cold, or like those, which are usually termed nervous, as the head-ach
or hemicrania, do not excite the organ into greater action; but in this
case I imagine the pains of sickness or of nausea counteract or destroy the
pleasurable sensation, which seems necessary to digestion, as shewn in
Sect. XXXIII. 1. 1. The peristaltic motions of the fibres of the stomach
become enfeebled by the want of this stimulus of pleasurable sensation, and
in consequence stop for a time, and then become inverted; for they cannot
become inverted without being previously stopped. Now that this inversion
of the trains of motion of the fibres of the stomach is owing to the
deficiency of pleasurable sensation is evinced from this circumstance, that
a nauseous idea excited by words will produce vomiting as effectually us a
nauseous drug.
Hence it appears, that the act of nausea or vomiting expends less sensorial
power than the usual peristaltic motions of the stomach in the digestion of
our aliment; and that hence there is a greater quantity of sensorial power
becomes accumulated in the fibres of the stomach, and more of it in
consequence to spare for the action of those parts of the system, which are
thus associated with the stomach, as of the whole absorbent series of
vessels, and which are at the same time excited by their usual stimuli.
From this we can understand, how after the operation of an emetic the
stomach becomes more irritable and sensible to the stimulus, and the
pleasure of food; since as the sensorial power becomes accumulated during
the nausea and vomiting, the digestive power is afterwards exerted more
forceably for a time. It should, however, be here remarked, that though
vomiting is in general produced by the defect of this stimulus of
pleasurable sensation, as when a nauseous drug is administered; yet in long
continued vomiting, as in sea-sickness, or from habitual dram-drinking, it
arises from deficiency of sensorial power, which in the former case is
exhausted by the increased exertion of the irritative ideas of vision, and
in the latter by the frequent application of an unnatural stimulus.
4. An example of the fourth circumstance above mentioned, where both the
primary and secondary parts of a train of motions proceed with energy less
than natural, may be observed in the dyspnoea, which occurs in going into a
very cold bath, and which has been described and explained in Sect. XXXII.
3. 2.
And by the increased debility of the pulsations of the heart and arteries
during the operation of an emetic. Secondly, from the slowness and
intermission of the pulsations of the heart from the incessant efforts to
vomit occasioned by an overdose of digitalis. And thirdly, from the total
stoppage of the motions of the heart, or death, in consequence of the
torpor of the stomach, when affected with the commencement or cold paroxysm
of the gout. See Sect. XXV. 17.
II. 1. The primary and secondary parts of the trains of sensitive
association reciprocally affect each other in different manners. 1. The
increased sensation of the primary part may cease, when that of the
secondary part commences. 2. The increased action of the primary part may
cease, when that of the secondary part commences. 3. The primary part may
have increased sensation, and the secondary part increased action. 4. The
primary part may have increased action, and the secondary part increased
sensation.
Examples of the first mode, where the increased sensation of the primary
part of a train of sensitive association ceases, when that of the secondary
part commences, are not unfrequent; as this is the general origin of those
pains, which continue some time without being attended with inflammation,
such as the pain at the pit of the stomach from a stone at the neck of the
gall-bladder, and the pain of strangury in the glans penis from a stone at
the neck of the urinary bladder. In both these cases the part, which is
affected secondarily, is believed to be much more sensible than the part
primarily affected, as described in the catalogue of diseases, Class II. 1.
1. 11. and IV. 2. 2. 2. and IV. 2. 2. 4.
The hemicrania, or nervous headach, as it is called, when it originates
from a decaying tooth, is another disease of this kind; as the pain of the
carious tooth always ceases, when the pain over one eye and temple
commences. And it is probable, that the violent pains, which induce
convulsions in painful epilepsies, are produced in the same manner, from a
more sensible part sympathizing with a diseased one of less sensibility.
See Catalogue of Diseases, Class IV. 2. 2. 8. and III. 1. 1. 6.
The last tooth, or dens sapientiæ, of the upper jaw most frequently decays
first, and is liable to produce pain over the eye and temple of that side.
The last tooth of the under-jaw is also liable to produce a similar
hemicrania, when it begins to decay. When a tooth in the upper-jaw is the
cause of the headach, a slighter pain is sometimes perceived on the
cheek-bone. And when a tooth in the lower-jaw is the cause of headach, a
pain sometimes affects the tendons of the muscles of the neck, which are
attached near the jaws. But the clavus hystericus, or pain about the middle
of the parietal bone on one side of the head, I have seen produced by the
second of the molares, or grinders, of the under-jaw; of which I shall
relate the following case. See Class IV. 2. 2. 8.
Mrs. ----, about 30 years of age, was seized with great pain about the
middle of the right parietal bone, which had continued a whole day before I
saw her, and was so violent as to threaten to occasion convulsions. Not
being able to detect a decaying tooth, or a tender one, by examination with
my eye, or by striking them with a tea-spoon, and fearing bad consequences
from her tendency to convulsion, I advised her to extract the last tooth of
the under-jaw on the affected side; which was done without any good effect.
She was then directed to lose blood, and to take a brisk cathartic; and
after that had operated, about 60 drops of laudanum were given her, with
large doses of bark; by which the pain was removed. In about a fortnight
she took a cathartic medicine by ill advice, and the pain returned with
greater violence in the same place; and, before I could arrive, as she
lived 30 miles from me, she suffered a paralytic stroke; which affected her
limbs and her face on one side, and relieved the pain of her head.
About a year afterwards I was again called to her on account of a pain as
violent as before exactly on the same part of the other parietal bone. On
examining her mouth I found the second molaris of the under-jaw on the side
before affected was now decayed, and concluded, that this tooth had
occasioned the stroke of the palsy by the pain and consequent exertion it
had caused. On this account I earnestly entreated her to allow the sound
molaris of the same jaw opposite to the decayed one to be extracted; which
was forthwith done, and the pain of her head immediately ceased, to the
astonishment of her attendants.
In the cases above related of the pain existing in a part distant from the
seat of the disease, the pain is owing to defect of the usual motions of
the painful part. This appears from the coldness, paleness, and emptiness
of the affected vessels, or of the extremities of the body in general, and
from there being no tendency to inflammation. The increased action of the
primary part of these associated motions, as of the hepatic termination of
the bile-duct; from the stimulus of a gall-stone, or of the interior
termination of the urethra from the stimulus of a stone in the bladder, or
lastly, of a decaying tooth in hemicrania, deprives the secondary part of
these associated motions, namely, the exterior terminations of the
bile-duct or urethra, or the pained membranes of the head in hemicrania, of
their natural share of sensorial power: and hence the secondary parts of
these sensitive trains of association become pained from the deficiency of
their usual motions, which is accompanied with deficiency of secretions and
of heat. See Sect. IV. 5. XII. 5. 3. XXXIV. 1.
Why does the pain of the primary part of the association cease, when that
of the secondary part commences? This is a question of intricacy, but
perhaps not inexplicable. The pain of the primary part of these associated
trains of motion was owing to too great stimulus, as of the stone at the
neck of the bladder, and was consequently caused by too great action of the
pained part. This greater action than natural of the primary part of these
associated motions, by employing or expending the sensorial power of
irritation belonging to the whole associated train of motions, occasioned
torpor, and consequent pain in the secondary part of the associated train;
which was possessed of greater sensibility than the primary part of it. Now
the great pain of the secondary part of the train, as soon as it commences,
employs or expends the sensorial power of sensation belonging to the whole
associated train of motions; and in consequence the motions of the primary
part, though increased by the stimulus of an extraneous body, cease to be
accompanied with pain or sensation.
If this mode of reasoning be just it explains a curious fact, why when two
parts of the body are strongly stimulated, the pain is felt only in one of
them, though it is possible by voluntary attention it may be alternately
perceived in them both. In the same manner, when two new ideas are
presented to us from the stimulus of external bodies, we attend to but one
of them at a time. In other words, when one set of fibres, whether of the
muscles or organs of sense, contract so strongly as to excite much
sensation; another set of fibres contracting more weakly do not excite
sensation at all, because the sensorial power of sensation is pre-occupied
by the first set of fibres. So we cannot will more than one effect at once,
though by associations previously formed we can move many fibres in
combination.
Thus in the instances above related, the termination of the bile duct in
the duodenum, and the exterior extremity of the urethra, are more sensible
than their other terminations. When these parts are deprived of their usual
motions by deficiency of sensorial power, as above explained, they become
painful according to law the fifth in Section IV. and the less pain
originally excited by the stimulus of concreted bile, or of a stone at
their other extremities ceases to be perceived. Afterwards, however, when
the concretions of bile, or the stone on the urinary bladder, become more
numerous or larger, the pain from their increased stimulus becomes greater
than the associated pain; and is then felt at the neck of the gall bladder
or urinary bladder; and the pain of the glans penis, or at the pit of the
stomach, ceases to be perceived.
2. Examples of the second mode, where the increased action of the primary
part of a train of sensitive association ceases, when that of the secondary
part commences, are also not unfrequent; as this is the usual manner of the
translation of inflammations from internal to external parts of the system,
such as when an inflammation of the liver or stomach is translated to the
membranes of the foot, and forms the gout; or to the skin of the face, and
forms the rosy drop; or when an inflammation of the membranes of the
kidneys is translated to the skin of the loins, and forms one kind of
herpes, called shingles; in these cases by whatever cause the original
inflammation may have been produced, as the secondary part of the train of
sensitive association is more sensible, it becomes exerted with greater
violence than the first part of it; and by both its increased pain, and the
increased motion of its fibres, so far diminishes or exhausts the sensorial
power of sensation; that the primary part of the train being less sensible
ceases both to feel pain, and to act with unnatural energy.
3. Examples of the third mode, where the primary part of a train of
sensitive association of motions may experience increased sensation, and
the secondary part increased action, are likewise not unfrequent; as it is
in this manner that most inflammations commence. Thus, after standing some
time in snow, the feet become affected with the pain of cold, and a common
coryza, or inflammation of the membrane of the nostrils, succeeds. It is
probable that the internal inflammations, as pleurisies, or hepatitis,
which are produced after the cold paroxysm of fever, originate in the same
manner from the sympathy of those parts with some others, which were
previously pained from quiescence; as happens to various parts of the
system during the cold fits of fevers. In these cases it would seem, that
the sensorial power of sensation becomes accumulated during the pain of
cold, as the torpor of the vessels occasioned by the defect of heat
contributes to the increase or accumulation of the sensorial power of
irritation, and that both these become exerted on some internal part, which
was not rendered torpid by the cold which affected the external parts, nor
by its association with them; or which sooner recovered its sensibility.
This requires further consideration.
4. An example of the fourth mode, or where the primary part of a sensitive
association of motions may have increased action, and the secondary part
increased sensation, may be taken from the pain of the shoulder, which
attends inflammation of the membranes of the liver, see Class IV. 2. 2. 9.;
in this circumstance so much sensorial power seems to be expended in the
violent actions and sensations of the inflamed membranes of the liver, that
the membranes associated with them become quiescent to their usual stimuli,
and painful in consequence.
There may be other modes in which the primary and secondary parts of the
trains of associated sensitive motions may reciprocally affect each other,
as may be seen by looking over Class IV. in the catalogue of diseases; all
which may probably be resolved into the plus and minus of sensorial power,
but we have not yet had sufficient observations made upon them with a view
to this doctrine.
III. The associated trains of our ideas may have sympathies, and their
primary and secondary parts affect each other in some manner similar to
those above described; and may thus occasion various curious phenomena not
yet adverted to, besides those explained in the Sections on Dreams,
Reveries, Vertigo, and Drunkenness; and may thus disturb the deductions of
our reasonings, as well as the streams of our imaginations; present us with
false degrees of fear, attach unfounded value to trivial circumstances;
give occasion to our early prejudices and antipathies; and thus embarrass
the happiness of our lives. A copious and curious harvest might be reaped
from this province of science, in which, however, I shall not at present
wield my sickle.
* * * * *
SECT. XXXVI.
OF THE PERIODS OF DISEASES.
I. _Muscles excited by volition soon cease to contract, or by
sensation, or by irritation, owing to the exhaustion of sensorial
power. Muscles subjected to less stimulus have their sensorial power
accumulated. Hence the periods of some fevers. Want of irritability
after intoxication._ II. 1. _Natural actions catenated with daily
habits of life._ 2. _With solar periods. Periods of sleep. Of
evacuating the bowels._ 3. _Natural actions catenated with lunar
periods. Menstruation. Venereal orgasm of animals. Barrenness._ III.
_Periods of diseased animal actions from stated returns of nocturnal
cold, from solar and lunar influence. Periods of diurnal fever, hectic
fever, quotidian, tertian, quartan fever. Periods of gout, pleurisy, of
fevers with arterial debility, and with arterial strength, Periods of
rhaphania, of nervous cough, hemicrania, arterial hæmorrhages,
hæmorrhoids, hæmoptoe, epilepsy, palsy, apoplexy, madness._ IV.
_Critical days depend on lunar periods. Lunar periods in the small
pox._
I. If any of our muscles be made to contract violently by the power of
volition, as those of the fingers, when any one hangs by his hands on a
swing, fatigue soon ensues; and the muscles cease to act owing to the
temporary exhaustion of the spirit of animation; as soon as this is again
accumulated in the muscles, they are ready to contract again by the efforts
of volition.
Those violent muscular actions induced by pain become in the same manner
intermitted and recurrent; as in labour-pains, vomiting, tenesmus,
strangury; owing likewise to the temporary exhaustion of the spirit of
animation, as above mentioned.
When any stimulus continues long to act with unnatural violence, so as to
produce too energetic action of any of our moving organs, those motions
soon cease, though the stimulus continues to act; as in looking long on a
bright object, as on an inch-square of red silk laid on white paper in the
sunshine. See Plate I. in Sect. III. 1.
On the contrary, where less of the stimulus of volition, sensation, or
irritation, have been applied to a muscle than usual; there appears to be
an accumulation of the spirit of animation in the moving organ; by which it
is liable to act with greater energy from less quantity of stimulus, than
was previously necessary to excite it into so great action; as after having
been immersed in snow the cutaneous vessels of our hands are excited into
stronger action by the stimulus of a less degree of heat, than would
previously have produced that effect.
From hence the periods of some fever-fits may take their origin, either
simply, or by their accidental coincidence with lunar and solar periods, or
with the diurnal periods of heat and cold, to be treated of below; for
during the cold fit at the commencement of a fever, from whatever cause
that cold fit may have been induced, it follows, 1. That the spirit of
animation must become accumulated in the parts, which exert during this
cold fit less than their natural quantity of action. 2. If the cause
producing the cold fit does not increase, or becomes diminished; the parts
before benumbed or inactive become now excitable by smaller stimulus, and
are thence thrown into more violent action than is natural; that is a hot
fit succeeds the cold one. 3. By the energetic action of the system during
the hot fit, if it continues long, an exhaustion of the spirit of animation
takes place; and another cold fit is liable to succeed, from the moving
system not being excitable into action from its usual stimulus. This
inirritability of the system from a too great previous stimulus, and
consequent exhaustion of sensorial power, is the cause of the general
debility, and sickness, and head-ach, some hours after intoxication. And
hence we see one of the causes of the periods of fever-fits; which however
are frequently combined with the periods of our diurnal habits, or of heat
and cold, or of solar or lunar periods.
When besides the tendency to quiescence occasioned by the expenditure of
sensorial power during the hot fit of fever, some other cause of torpor, as
the solar or lunar periods, is necessary to the introduction of a second
cold fit; the fever becomes of the intermittent kind; that is, there is a
space of time intervenes between the end of the hot fit, and the
commencement of the next cold one. But where no exteriour cause is
necessary to the introduction of the second cold fit; no such interval of
health intervenes; but the second cold fit commences, as soon as the
sensorial power is sufficiently exhausted by the hot fit; and the fever
becomes continual.
II. 1. The following are natural animal actions, which are frequently
catenated with our daily habits of life, as well as excited by their
natural irritations. The periods of hunger and thirst become catenated with
certain portions of time, or degrees of exhaustion, or other diurnal habits
of life. And if the pain of hunger be not relieved by taking food at the
usual time, it is liable to cease till the next period of time or other
habits recur; this is not only true in respect to our general desire of
food, but the kinds of it also are governed by this periodical habit;
insomuch that beer taken to breakfast will disturb the digestion of those,
who have been accustomed to tea; and tea taken at dinner will disagree with
those, who have been accustomed to beer. Whence it happens, that those, who
have weak stomachs, will be able to digest more food, if they take their
meals at regular hours; because they have both the stimulus of the aliment
they take, and the periodical habit, to assist their digestion.
The periods of emptying the bladder are not only dependent on the acrimony
or distention of the water in it, but are frequently catenated with
external cold applied to the skin, as in cold bathing, or washing the
hands; or with other habits of life, as many are accustomed to empty the
bladder before going to bed, or into the house after a journey, and this
whether it be full or not.
Our times of respiration are not only governed by the stimulus of the blood
in the lungs, or our desire of fresh air, but also by our attention to the
hourly objects before us. Hence when a person is earnestly contemplating an
idea of grief, he forgets to breathe, till the sensation in his lungs
becomes very urgent; and then a sigh succeeds for the purpose of more
forceably pushing forwards the blood, which is accumulated in the lungs.
Our times of respiration are also frequently governed in part by our want
of a steady support for the actions of our arms, and hands, as in threading
a needle, or hewing wood, or in swimming; when we are intent upon these
objects, we breathe at the intervals of the exertion of the pectoral
muscles.
2. The following natural animal actions are influenced by solar periods.
The periods of sleep and of waking depend much on the solar period, for we
are inclined to sleep at a certain hour, and to awake at a certain hour,
whether we have had more or less fatigue during the day, if within certain
limits; and are liable to wake at a certain hour, whether we went to bed
earlier or later, within certain limits. Hence it appears, that those who
complain of want of sleep, will be liable to sleep better or longer, if
they accustom themselves to go to rest, and to rise, at certain hours.
The periods of evacuating the bowels are generally connected with some part
of the solar day, as well as with the acrimony or distention occasioned by
the feces. Hence one method of correcting costiveness is by endeavouring to
establish a habit of evacuation at a certain hour of the day, as
recommended by Mr. Locke, which may be accomplished by using daily
voluntary efforts at those times, joined with the usual stimulus of the
material to be evacuated.
3. The following natural animal actions are connected with lunar periods.
1. The periods of female menstruation are connected with lunar periods to
great exactness, in some instances even to a few hours. These do not
commence or terminate at the full or change, or at any other particular
part of the lunation, but after they have commenced at any part of it, they
continue to recur at that part with great regularity, unless disturbed by
some violent circumstance, as explained in Sect. XXXII. No. 6. their return
is immediately caused by deficient venous absorption, which is owing to the
want of the stimulus, designed by nature, of amatorial copulation, or of
the growing fetus. When the catamenia returns sooner than the period of
lunation, it shows a tendency of the constitution to inirritability; that
is to debility, or deficiency of sensorial power, and is to be relieved by
small doses of steel and opium.
The venereal orgasm of birds and quadrupeds seems to commence, or return
about the most powerful lunations at the vernal or autumnal equinoxes; but
if it be disappointed of its object, it is said to recur at monthly
periods; in this respect resembling the female catamenia. Whence it is
believed, that women are more liable to become pregnant at or about the
time of their catamenia, than at the intermediate times; and on this
account they are seldom much mistaken in their reckoning of nine lunar
periods from the last menstruation; the inattention to this may sometimes
have been the cause of supposed barrenness, and is therefore worth the
observation of those, who wish to have children.
III. We now come to the periods of diseased animal actions. The periods of
fever-fits, which depend on the stated returns of nocturnal cold, are
discussed in Sect. XXXII. 3. Those, which originate or recur at solar or
lunar periods, are also explained in Section XXXII. 6. These we shall here
enumerate; observing, however, that it is not more surprising, that the
influence of the varying attractions of the sun and moon, should raise the
ocean into mountains, than that it should affect the nice sensibilities of
animal bodies; though the manner of its operation on them is difficult to
be understood. It is probable however, that as this influence gradually
lessens during the course of the day, or of the lunation, or of the year,
some actions of our system become less and less; till at length a total
quiescence of some part is induced; which is the commencement of the
paroxysms of fever, of menstruation, of pain with decreased action of the
affected organ, and of consequent convulsion.
1. A diurnal fever in some weak people is distinctly observed to come on
towards evening, and to cease with a moist skin early in the morning,
obeying the solar periods. Persons of weak constitutions are liable to get
into better spirits at the access of the hot fit of this evening fever; and
are thence inclined to sit up late; which by further enfeebling them
increases the disease; whence they lose their strength and their colour.
2. The periods of hectic fever, supposed to arise from absorption of
matter, obeys the diurnal periods like the above, having the exacerbescence
towards evening, and its remission early in the morning, with sweats, or
diarrhoea, or urine with white sediment.
3. The periods of quotidian fever are either catenated with solar time, and
return at the intervals of twenty-four hours; or with lunar time, recurring
at the intervals of about twenty-five hours. There is great use in knowing
with what circumstances the periodical return or new morbid motions are
conjoined, as the most effectual times of exhibiting the proper medicines
are thus determined. So if the torpor, which ushers in an ague fit, is
catenated with the lunar day: it is known, when the bark or opium must be
given, so as to exert its principal effect about the time of the expected
return. Solid opium should be given about an hour before the expected cold
fit; liquid opium and wine about half an hour; the bark repeatedly for six
or eight hours previous to the expected return.
4. The periods of tertian fevers, reckoned from the commencement of one
cold fit to the commencement of the next cold fit, recur with solar
intervals of forty-eight hours, or with lunar ones of about fifty hours.
When these of recurrence begin one or two hours earlier than the solar
period, it shews, that the torpor or cold fit is produced by less external
influence; and therefore that it is more liable to degenerate into a fever
with only remissions; so when menstruation recurs sooner than the period of
lunation, it shews a tendency of the habit to torpor of inirritability.
5. The periods of quartan fevers return at solar intervals of seventy-two
hours, or at lunar ones of about seventy-four hours and an half. This kind
of ague appears most in moist cold autumns, and in cold countries replete
with marshes. It is attended with greater debility, and its cold access
more difficult to prevent. For where there is previously a deficiency of
sensorial power, the constitution is liable to run into greater torpor from
any further diminution of it; two ounces of bark and some steel should be
given on the day before the return of the cold paroxysm, and a pint of wine
by degrees a few hours before its return, and thirty drops of laudanum one
hour before the expected cold fit.
6. The periods of the gout generally commence about an hour before
sun-rise, which is usually the coldest part of the twenty-four hours. The
greater periods of the gout seem also to observe the solar influence,
returning about the same season of the year.
7. The periods of the pleurisy recur with exacerbation of the pain and
fever about sun-set, at which time venesection is of most service. The same
may be observed of the inflammatory rheumatism, and other fevers with
arterial strength, which seem to obey solar periods; and those with
debility seem to obey lunar ones.
8. The periods of fevers with arterial debility seem to obey the lunar day,
having their access daily nearly an hour later; and have sometimes two
accesses in a day, resembling the lunar effects upon the tides.
9. The periods of rhaphania, or convulsions of the limbs from rheumatic
pains, seem to be connected with solar influence, returning at nearly the
same hour for weeks together, unless disturbed by the exhibition of
powerful doses of opium.
So the periods of Tussis ferina, or violent cough with slow pulse, called
nervous cough, recurs by solar periods. Five grains of opium, given at the
time the cough commenced disturbed the period, from seven in the evening to
eleven, at which time it regularly returned for some days, during which
time the opium was gradually omitted. Then 120 drops of laudanum were given
an hour before the access of the cough, and it totally ceased. The laudanum
was continued a fortnight, and then gradually discontinued.
10. The periods of hemicrania, and of painful epilepsy, are liable to obey
lunar periods, both in their diurnal returns, and in their greater periods
of weeks, but are also induced by other exciting causes.
11. The periods of arterial hæmorrhages seem to return at solar periods
about the same hour of the evening or morning. Perhaps the venous
hæmorrhages obey the lunar periods, as the catamenia, and hæmorrhoids.
12. The periods of the hæmorrhoids, or piles, in some recur monthly, in
others only at the greater lunar influence about the equinoxes.
13. The periods of hæmoptoe sometimes obey solar influence, recurring early
in the morning for several days; and sometimes lunar periods, recurring
monthly; and sometimes depend on our hours of sleep. See Class I. 2. 1. 9.
14. Many of the first periods of epileptic fits obey the monthly lunation
with some degree of accuracy; others recur only at the most powerful
lunations before the vernal equinox, and after the autumnal one; but when
the constitution has gained a habit of relieving disagreeable sensations by
this kind of exertion, the fit recurs from any slight cause.
15. The attack of palsy and apoplexy are known to recur with great
frequency about the equinoxes.
16. There are numerous instances of the effect of the lunations upon the
periods of insanity, whence the name of lunatic has been given to those
afflicted with this disease.
IV. The critical days, in which fevers are supposed to terminate, have
employed the attention of medical philosophers from the days of Hippocrates
to the present time. In whatever part of a lunation a fever commences,
which owes either its whole cause to solar and lunar influence, or to this
in conjunction with other causes; it would seem, that the effect would be
the greatest at the full and new moon, as the tides rise highest at those
times, and would be the least at the quadratures; thus if a fever-fit
should commence at the new or full moon, occasioned by the solar and lunar
attraction diminishing some chemical affinity of the particles of blood,
and thence decreasing their stimulus on our sanguiferous system, as
mentioned in Sect. XXXII. 6. this effect will daily decrease for the first
seven days, and will then increase till about the fourteenth day, and will
again decrease till about the twenty-first day, and increase again till the
end of the lunation. If a fever-fit from the above cause should commence on
the seventh day after either lunation, the reverse of the above
circumstances would happen. Now it is probable, that those fevers, whose
crisis or terminations are influenced by lunations, may begin at one or
other of the above times, namely at the changes or quadratures; though
sufficient observations have not been made to ascertain this circumstance.
Hence I conclude, that the small-pox and measles have their critical days,
not governed by the times required for certain chemical changes in the
blood, which affect or alter the stimulus of the contagious matter, but
from the daily increasing or decreasing effect of this lunar link of
catenation, as explained in Section XVII. 3. 3. And as other fevers
terminate most frequently about the seventh, fourteenth, twenty-first, or
about the end of four weeks, when no medical assistance has disturbed their
periods, I conclude, that these crises, or terminations, are governed by
periods of the lunations; though we are still ignorant of their manner of
operation.
In the distinct small-pox the vestiges of lunation are very apparent, after
inoculation a quarter of a lunation precedes the commencement of the fever,
another quarter terminates with the complete eruption, another quarter with
the complete maturation, and another quarter terminates the complete
absorption of a material now rendered inoffensive to the constitution.
* * * * *
SECT. XXXVII.
OF DIGESTION, SECRETION, NUTRITION.
I. _Crystals increase by the greater attraction of their sides.
Accretion by chemical precipitations, by welding, by pressure, by
agglutination._ II. _Hunger, digestion, why it cannot be imitated out
of the body. Lacteals absorb by animal selection or appetency._ III.
_The glands and pores absorb nutritious particles by animal selection.
Organic particles of Buffon. Nutrition applied at the time of
elongation of fibres. Like inflammation._ IV. _It seems easier to have
preserved animals than to reproduce them. Old age and death from
inirritability. Three causes of this. Original fibres of the organs of
sense and muscles unchanged._ V. _Art of producing long life._
I. The larger crystals of saline bodies may be conceived to arise from the
combination of smaller crystals of the same form, owing to the greater
attractions of their sides than of their angles. Thus if four cubes were
floating in a fluid, whose friction or resistance is nothing, it is certain
the sides of these cubes would attract each other stronger than their
angles; and hence that these four smaller cubes would so arrange themselves
as to produce one larger one.
There are other means of chemical accretion, such as the depositions of
dissolved calcareous or siliceous particles, as are seen in the formation
of the stalactites of limestone in Derbyshire, or of calcedone in Cornwall.
Other means of adhesion are produced by heat and pressure, as in the
welding of iron-bars; and other means by simple pressure, as in forcing two
pieces of caoutchou, or elastic gum, to adhere; and lastly, by the
agglutination of a third substance penetrating the pores of the other two,
as in the agglutination of wood by means of animal gluten. Though the
ultimate particles of animal bodies are held together during life, as well
as after death, by their specific attraction of cohesion, like all other
matter; yet it does not appear, that their original organization was
produced by chemical laws, and their production and increase must therefore
only be looked for from the laws of animation.
II. When the pain of hunger requires relief, certain parts of the material
world, which surround us, when applied to our palates, excite into action
the muscles of deglutition; and the material is swallowed into the stomach.
Here the new aliment becomes mixed with certain animal fluids, and
undergoes a chemical process, termed digestion; which however chemistry has
not yet learnt to imitate out of the bodies of living animals or
vegetables. This process seems very similar to the saccharine process in
the lobes of farinaceous seeds, as of barley, when it begins to germinate;
except that, along with the sugar, oil and mucilage are also produced;
which form the chyle of animals, which is very similar to their milk.
The reason, I imagine, why this chyle-making, or saccharine process, has
not yet been imitated by chemical operations, is owing to the materials
being in such a situation in respect to warmth, moisture, and motion; that
they will immediately change into the vinous or acetous fermentation;
except the new sugar be absorbed by the numerous lacteal or lymphatic
vessels, as soon as it is produced; which is not easy to imitate in the
laboratory.
These lacteal vessels have mouths, which are irritated into action by the
stimulus of the fluid, which surrounds them; and by animal selection, or
appetency, they absorb such part of the fluid as is agreeable to their
palate; those parts, for instance, which are already converted into chyle,
before they have time to undergo another change by a vinous or acetous
fermentation. This animal absorption of fluid is almost visible to the
naked eye in the action of the puncta lacrymalia; which imbibe the tears
from the eye, and discharge them again into the nostrils.
III. The arteries constitute another reservoir of a changeful fluid; from
which, after its recent oxygenation in the lungs, a further animal
selection of various fluids is absorbed by the numerous glands; these
select their respective fluids from the blood, which is perpetually
undergoing a chemical change; but the selection by these glands, like that
of the lacteals, which open their mouths into the digesting aliment in the
stomach, is from animal appetency, not from chemical affinity; secretion
cannot therefore be imitated in the laboratory, as it consists in a
selection of part of a fluid during the chemical change of that fluid.
The mouths of the lacteals, and lymphatics, and the ultimate terminations
of the glands, are finer than can easily be conceived; yet it is probable,
that the pores, or interstices of the parts, or coats, which constitute
these ultimate vessels, may still have greater tenuity; and that these
pores from the above analogy must posses a similar power of irritability,
and absorb by their living energy the particles of fluid adapted to their
purposes, whether to replace the parts abraded or dissolved, or to elongate
and enlarge themselves. Not only every kind of gland is thus endued with
its peculiar appetency, and selects the material agreeable to its taste
from the blood, but every individual pore acquires by animal selection the
material, which it wants; and thus nutrition seems to be performed in a
manner so similar to secretion; that they only differ in the one retaining,
and the other parting again with the particles, which they have selected
from the blood.
This way of accounting for nutrition from stimulus, and the consequent
animal selection of particles, is much more analogous to other phenomena of
the animal microcosm, than by having recourse to the microscopic
animalcula, or organic particles of Buffon, and Needham; which being
already compounded must themselves require nutritive particles to continue
their own existence. And must be liable to undergo a change by our
digestive or secretory organs; otherwise mankind would soon resemble by
their theory the animals, which they feed upon. He, who is nourished by
beef or venison, would in time become horned; and he, who feeds on pork or
bacon, would gain a nose proper for rooting into the earth, as well as for
the perception of odours.
The whole animal system may be considered as consisting of the extremities
of the nerves, or of having been produced from them; if we except perhaps
the medullary part of the brain residing in the head and spine, and in the
trunks of the nerves. These extremities of the nerves are either of those
of locomotion, which are termed muscular fibres; or of those of sensation,
which constitute the immediate organs of sense, and which have also their
peculiar motions. Now as the fibres, which constitute the bones and
membranes, possessed originally sensation and motion; and are liable again
to possess them, when they become inflamed; it follows, that those were,
when first formed, appendages to the nerves of sensation or locomotion, or
were formed from them. And that hence all these solid parts of the body, as
they have originally consisted of extremities of nerves, require an
apposition of nutritive particles of a similar kind, contrary to the
opinion of Buffon and Needham above recited.
Lastly, as all these filaments have possessed, or do possess, the power of
contraction, and of consequent inertion or elongation; it seems probable,
that the nutritive particles are applied during their times of elongation;
when their original constituent particles are removed to a greater distance
from each other. For each muscular or sensual fibre may be considered as a
row or string of beads; which approach, when in contraction, and recede
during its rest or elongation; and our daily experience shews us, that
great action emaciates the system, and that it is repaired during rest.
Something like this is seen out of the body; for if a hair, or a single
untwisted fibre of flax or silk, be soaked in water; it becomes longer and
thicker by the water, which is absorbed into its pores. Now if a hair could
be supposed to be thus immersed in a solution of particles similar to
those, which compose it; one may imagine, that it might be thus increased
in weight and magnitude; as the particles of oak-bark increase the
substance of the hides of beasts in the process of making leather. I
mention these not as philosophic analogies, but as similes to facilitate
our ideas, how an accretion of parts may be effected by animal appetences,
or selections, in a manner somewhat similar to mechanical or chemical
attractions.
If those new particles of matter, previously prepared by digestion and
sanguification, only supply the places of those, which have been abraded by
the actions of the system, it is properly termed nutrition. If they are
applied to the extremities of the nervous fibrils, or in such quantity as
to increase the length or crassitude of them, the body becomes at the same
time enlarged, and its growth is increased, as well as its deficiences
repaired.
In this last case something more than a simple apposition or selection of
particles seems to be necessary; as many parts of the system during its
growth are caused to recede from those, with which they were before in
contact; as the ends of the bones, or cartilages, recede from each other,
as their growth advances: this process resembles inflammation, as appears
in ophthalmy, or in the production of new flesh in ulcers, where old
vessels are enlarged, and new ones produced; and like that is attended with
sensation. In this situation the vessels become distended with blood, and
acquire greater sensibility, and may thus be compared to the erection of
the penis, or of the nipples of the breasts of women; while new particles
become added at the same time; as in the process of nutrition above
described.
When only the natural growth of the various parts of the body are produced,
a pleasurable sensation attends it, as in youth, and perhaps in those, who
are in the progress of becoming fat. When an unnatural growth is the
consequence, as in inflammatory diseases, a painful sensation attends the
enlargement of the system.
IV. This apposition of new parts, as the old ones disappear, selected from
the aliment we take, first enlarges and strengthens our bodies for twenty
years, for another twenty years it keeps us in health and vigour, and adds
strength and solidity to the system; and then gradually ceases to nourish
us properly, and for another twenty years we gradually sink into decay, and
finally cease to act, and to exist.
On considering this subject one should have imagined at first view, that it
might have been easier for nature to have supported her progeny for ever in
health and life, than to have perpetually reproduced them by the wonderful
and mysterious process of generation. But it seems our bodies by long habit
cease to obey the stimulus of the aliment, which should support us. After
we have acquired our height and solidity we make no more new parts, and the
system obeys the irritations, sensations, volitions; and associations,
with, less and less energy, till the whole sinks into inaction.
Three causes may conspire to render our nerves less excitable, which have
been already mentioned, 1. If a stimulus be greater than natural, it
produces too great an exertion of the stimulated organ, and in consequence
exhausts the spirit of animation; and the moving organ ceases to act, even
though the stimulus be continued. And though rest will recruit this
exhaustion, yet some degree of permanent injury remains, as is evident
after exposing the eyes long to too strong a light. 2. If excitations
weaker than natural be applied, so as not to excite the organ into action,
(as when small doses of aloe or rhubarb are exhibited,) they may be
gradually increased, without exciting the organ into action; which will
thus acquire a habit of disobedience to the stimulus; thus by increasing
the dose by degrees, great quantities of opium or wine may be taken without
intoxication. See Sect. XII. 3. 1.
3. Another mode, by which life is gradually undermined, is when irritative
motions continue to be produced in consequence of stimulus, but are not
succeeded by sensation; hence the stimulus of contagious matter is not
capable of producing fever a second time, because it is not succeeded by
sensation. See Sect. XII. 3. 6. And hence, owing to the want of the general
pleasurable sensation, which ought to attend digestion and glandular
secretion, an irksomeness of life ensues; and, where this is in greater
excess, the melancholy of old age occurs, with torpor or debility.
From hence I conclude, that it is probable that the fibrillæ, or moving
filaments at the extremities of the nerves of sense, and the fibres which
constitute the muscles (which are perhaps the only parts of the system that
are endued with contractile life) are not changed, as we advance in years,
like the other parts of the body; but only enlarged or elongated with our
growth; and in consequence they become less and less excitable into action.
Whence, instead of gradually changing the old animal, the generation of a
totally new one becomes necessary with undiminished excitability; which
many years will continue to acquire new parts, or new solidity, and then
losing its excitability in time, perish like its parent.
V. From this idea the art of preserving long health and life may be
deduced; which must consist in using no greater stimulus, whether of the
quantity or kind of our food and drink, or of external circumstances, such
as heat, and exercise, and wakefulness, than is sufficient to preserve us
in vigour; and gradually, as we grow old to increase the stimulus of our
aliment, as the irritability of our system increases.
The debilitating effects ascribed by the poet MARTIAL to the excessive use
of warm bathing in Italy, may with equal propriety be applied to the warm
rooms of England; which, with the general excessive stimulus of spirituous
or fermented liquors, and in some instances of immoderate venery,
contribute to shorten our lives.
_Balnea, vina, venus, corrumpunt corpora nostra_,
_At faciunt vitam balnea, vina, venus!_
Wine, women, warmth, against our lives combine;
But what is life without warmth, women, wine!
* * * * *
SECT. XXXVIII.
OF THE OXYGENATION OF THE BLOOD IN THE LUNGS, AND IN THE PLACENTA.
I. _Blood absorbs oxygene from the air, whence phosphoric acid changes
its colour, gives out heat, and some phlogistic material, and acquires
an ethereal spirit, which is dissipated in fibrous motion._ II. _The
placenta is a pulmonary organ like the gills of fish. Oxygenation of
the blood from air, from water, by lungs, by gills, by the placenta;
necessity of this oxygenation to quadrupeds, to fish, to the foetus in
utero. Placental vessels inserted into the arteries of the mother. Use
of cotyledons in cows. Why quadrupeds have not sanguiferous lochia.
Oxygenation of the chick in the egg, of feeds._ III. _The liquor amnii
is not excrementitious. It is nutritious. It is found in the esophagus
and stomach, and forms the meconium. Monstrous births without heads.
Question of Dr. Harvey._
I. From the recent discoveries of many ingenious philosophers it appears,
that during respiration the blood imbibes the vital part of the air, called
oxygene, through the membranes of the lungs; and that hence respiration may
be aptly compared to a slow combustion. As in combustion the oxygene of the
atmosphere unites with some phlogistic or inflammable body, and forms an
acid (as in the production of vitriolic acid from sulphur, or carbonic acid
from charcoal,) giving out at the same time a quantity of the matter of
heat; so in respiration the oxygene of the air unites with the phlogistic
part of the blood, and probably produces phosphoric or animal acid,
changing the colour of the blood from a dark to a bright red; and probably
some of the matter of heat is at the same time given out according to the
theory of Dr. Crawford. But as the evolution of heat attends almost all
chemical combinations, it is probable, that it also attends the secretions
of the various fluids from the blood; and that the constant combinations or
productions of new fluids by means of the glands constitute the more
general source of animal heat; this seems evinced by the universal
evolution of the matter of heat in the blush of shame or of anger; in which
at the same time an increased secretion of the perspirable matter occurs;
and the partial evolution of it from topical inflammations, as in gout or
rheumatism, in which there is a secretion of new blood-vessels.
Some medical philosophers have ascribed the heat of animal bodies to the
friction of the particles of the blood against the sides of the vessels.
But no perceptible heat has ever been produced by the agitation of water,
or oil, or quicksilver, or other fluids; except those fluids have undergone
at the same time some chemical change, as in agitating milk or wine, till
they become sour.
Besides the supposed production of phosphoric acid, and change of colour of
the blood, and the production of carbonic acid, there would appear to be
something of a more subtile nature perpetually acquired from the
atmosphere; which is too fine to be long contained in animal vessels, and
therefore requires perpetual renovation; and without which life cannot
continue longer than a minute or two; this ethereal fluid is probably
secreted from the blood by the brain, and perpetually dissipated in the
actions of the muscles and organs of sense.
That the blood acquires something from the air, which is immediately
necessary to life, appears from an experiment of Dr. Hare (Philos.
Transact. abridged, Vol. III. p. 239.) who found, "that birds, mice, &c.
would live as long again in a vessel, where he had crowded in double the
quantity of air by a condensing engine, than they did when confined in air
of the common density." Whereas if some kind of deleterious vapour only was
exhaled from the blood in respiration; the air, when condensed into half
its compass, could not be supposed to receive so much of it.
II. Sir Edward Hulse, a physician of reputation at the beginning of the
present century, was of opinion, that the placenta was a respiratory organ,
like the gills of fish; and not an organ to supply nutriment to the foetus;
as mentioned in Derham's Physico-theology. Many other physicians seem to
have espoused the same opinion, as noticed by Haller. Elem. Physiologiæ, T.
1. Dr. Gipson published a defence of this theory in the Medical Essays of
Edinburgh, Vol. I. and II. which doctrine is there controverted at large by
the late Alexander Monro; and since that time the general opinion has been,
that the placenta is an organ of nutrition only, owing perhaps rather to
the authority of so great a name, than to the validity of the arguments
adduced in its support. The subject has lately been resumed by Dr. James
Jeffray, and by Dr. Forester French, in their inaugural dissertations at
Edinburgh and at Cambridge; who have defended the contrary opinion in an
able and ingenious manner; and from whose Theses I have extracted many of
the following remarks.
First, by the late discoveries of Dr. Priestley, M. Lavoisier, and other
philosophers, it appears, that the basis of atmospherical air, called
oxygene, is received by the blood through the membranes of the lungs; and
that by this addition the colour of the blood is changed from a dark to a
light red. Secondly, that water possesses oxygene also as a part of its
composition, and contains air likewise in its pores; whence the blood of
fish receives oxygene from the water, or from the air it contains, by means
of their gills, in the same manner as the blood is oxygenated in the lungs
of air-breathing animals; it changes its colour at the same time from a
dark to a light red in the vessels of their gills, which constitute a
pulmonary organ adapted to the medium in which they live. Thirdly, that the
placenta consists of arteries carrying the blood to its extremities, and a
vein bringing it back, resembling exactly in structure the lungs and gills
above mentioned; and that the blood changes its colour from a dark to a
light red in passing through these vessels.
This analogy between the lungs and gills of animals, and the placenta of
the fetus, extends through a great variety of other circumstances; thus
air-breathing creatures and fish can live but a few minutes without air or
water; or when they are confined in such air or water, as has been spoiled
by their own respiration; the same happens to the fetus, which, as soon as
the placenta is separated from the uterus, must either expand its lungs,
and receive air, or die. Hence from the structure, as well as the use of
the placenta, it appears to be a respiratory organ, like the gills of fish,
by which the blood in the fetus becomes oxygenated.
From the terminations of the placental vessels not being observed to bleed
after being torn from the uterus, while those of the uterus effuse a great
quantity of florid arterial blood, the terminations of the placental
vessels would seem to be inserted into the arterial ones of the mother; and
to receive oxygenation from the passing currents of her blood through their
coats or membranes; which oxygenation is proved by the change of the colour
of the blood from dark to light red in its passage from the placental
arteries to the placental vein.
The curious structure of the cavities or lacunæ of the placenta,
demonstrated by Mr. J. Hunter, explain this circumstance. That ingenious
philosopher has shewn, that there are numerous cavities of lacunæ formed on
that side of the placenta, which is in contact with the uterus; those
cavities or cells are filled with blood from the maternal arteries, which
open into them; which blood is again taken up by the maternal veins, and is
thus perpetually changed. While the terminations of the placental arteries
and veins are spread in fine reticulation on the sides of these cells. And
thus, as the growing fetus requires greater oxygenation, an apparatus is
produced resembling exactly the air-cells of the lungs.
In cows, and other ruminating animals, the internal surface of the uterus
is unequal like hollow cups, which have been called cotyledons; and into
these cavities the prominencies of the numerous placentas, with which the
fetus of those animals is furnished, are inserted, and strictly adhere;
though they may be extracted without effusion of blood. These inequalities
of the uterus, and the numerous placentas in consequence, seem to be
designed for the purpose of expanding a greater surface for the
terminations of the placental vessels for the purpose of receiving
oxygenation from the uterine ones; as the progeny of this class of animals
are more completely formed before their nativity, than that of the
carnivorous classes, and must thence in the latter weeks of pregnancy
require greater oxygenation. Thus calves and lambs can walk about in a few
minutes after their birth; while puppies and kittens remain many days
without opening their eyes. And though on the separation of the cotyledons
of ruminating animals no blood is effused, yet this is owing clearly to the
greater power of contraction of their uterine lacunæ or alveoli. See
Medical Essays, Vol. V. page 144. And from the same cause they are not
liable to a sanguiferous menstruation.
The necessity of the oxygenation of the blood in the fetus is farther
illustrated by the analogy of the chick in the egg; which appears to have
its blood oxygenated at the extremities of the vessels surrounding the
yolk; which are spread on the air-bag at the broad end of the egg, and may
absorb oxygene through that moist membrane from the air confined behind it;
and which is shewn by experiments in the exhausted receiver to be
changeable though the shell.
This analogy may even be extended to the growing seeds of vegetables; which
were shewn by Mr. Scheele to require a renovation of the air over the
water, in which they were confined. Many vegetable seeds are surrounded
with air in their pods or receptacles, as peas, the fruit of staphylea, and
lichnis vesicaria; but it is probable, that those seeds, after they are
shed, as well as the spawn of fish, by the situation of the former on or
near the moist and aerated surface of the earth, and of the latter in the
ever-changing and ventilated water, may not be in need of an apparatus for
the oxygenation of their first blood, before the leaves of one, and the
gills of the other, are produced for this purpose.
III. 1. There are many arguments, besides the strict analogy between the
liquor amnii and the albumen ovi, which shew the former to be a nutritive
fluid; and that the fetus in the latter months of pregnancy takes it into
its stomach; and that in consequence the placenta is produced for some
other important purpose.
First, that the liquor amnii is not an excrementitious fluid is evinced,
because it is found in greater quantity, when the fetus is young,
decreasing after a certain period till birth. Haller asserts, "that in some
animals but a small quantity of this fluid remains at the birth. In the
eggs of hens it is consumed on the eighteenth day, so that at the exclusion
of the chick scarcely any remains. In rabbits before birth there is none."
Elem. Physiol. Had this been an excrementitious fluid, the contrary would
probably have occurred. Secondly, the skin of the fetus is covered with a
whitish crust or pellicle, which would seem to preclude any idea of the
liquor amnii being produced by any exsudation of perspirable matter. And it
cannot consist of urine, because in brute animals the urachus passes from
the bladder to the alantois for the express purpose of carrying off that
fluid; which however in the human fetus seems to be retained in the
distended bladder, as the feces are accumulated in the bowels of all
animals.
2. The nutritious quality of the liquid, which surrounds the fetus, appears
from the following considerations. 1. It is coagulable by heat, by nitrous
acid, and by spirit of wine, like milk, serum of blood, and other fluids,
which daily experience evinces to be nutritious. 2. It has a saltish taste
according to the accurate Baron Haller, not unlike the whey of milk, which
it even resembles in smell. 3. The white of the egg which constitutes the
food of the chick, is shewn to be nutritious by our daily experience;
besides the experiment of its nutritious effects mentioned by Dr. Fordyce
in his late Treatise on Digestion, p. 178; who adds, that it much resembles
the essential parts of the serum of blood.
3. A fluid similar to the fluid, with which the fetus is surrounded, except
what little change may be produced by a beginning digestion, is found in
the stomach of the fetus; and the white of the egg is found, in the same
manner in the stomach of the chick.
Numerous hairs, similar to those of its skin, are perpetually found among
the contents of the stomach in new-born calves; which must therefore have
licked themselves before their nativity. Blasii Anatom. See Sect. XVI. 2.
on Instinct.
The chick in the egg is seen gently to move in its surrounding fluid, and
to open and shut its mouth alternately. The same has been observed in
puppies. Haller's El. Phys. I. 8. p. 201.
A column of ice has been seen to reach down the oesophagus from the mouth
to the stomach in a frozen fetus; and this ice was the liquor amnii frozen.
The meconium, or first fæces, in the bowels of new-born infants evince,
that something has been digested; and what could this be but the liquor
amnii together with the recrements of the gastric juice and gall, which
were necessary for its digestion?
There have been recorded some monstrous births of animals without heads,
and consequently without mouths, which seem to have been delivered on
doubtful authority, or from inaccurate observation. There are two of such
monstrous productions however better attested; one of a human fetus,
mentioned by Gipson in the Scots Medical Essays; which having the gula
impervious was furnished with an aperture into the wind-pipe, which
communicated below into the gullet; by means of which the liquor amnii
might be taken into the stomach before nativity without danger of
suffocation, while the fetus had no occasion to breathe. The other
monstrous fetus is described by Vander Wiel, who asserts, that he saw a
monstrous lamb, which had no mouth; but instead of it was furnished with an
opening in the lower part of the neck into the stomach. Both these
instances evidently favour the doctrine of the fetus being nourished by the
mouth; as otherwise there had been no necessity for new or unnatural
apertures into the stomach, when the natural ones were deficient?
From these facts and observations we may safely infer, that the fetus in
the womb is nourished by the fluid which surrounds it; which during the
first period of gestation is absorbed by the naked lacteals; and is
afterwards swallowed into the stomach and bowels, when these organs are
perfected; and lastly that the placenta is an organ for the purpose of
giving due oxygenation to the blood of the fetus; which is more necessary,
or at least more frequently necessary, than even the supply of food.
The question of the great Harvey becomes thus easily answered. "Why is not
the fetus in the womb suffocated for want of air, when it remains there
even to the tenth month without respiration: yet if it be born in the
seventh or eighth month, and has once respired, it becomes immediately
suffocated for want of air, if its respiration be obstructed?"
For further information on this subject, the reader is referred to the
Tentamen Medicum of Dr. Jeffray, printed at Edinburgh in 1786. And it is
hoped that Dr. French will some time give his theses on this subject to the
public.
* * * * *
SECT. XXXIX.
OF GENERATION.
Felix, qui causas altà caligine mersas
Pandit, et evolvit tenuissima vincula rerum.
I. _Habits of acting and feeling of individuals attend the soul into a
future life, and attend the new embryon at the time of its production.
The new speck of entity absorbs nutriment, and receives oxygene.
Spreads the terminations of its vessels on cells, which communicate
with the arteries of the uterus; sometimes with those of the
peritoneum. Afterwards it swallows the liquor amnii, which it produces
by its irritation from the uterus, or peritoneum. Like insects in the
heads of calves and sheep. Why the white of egg is of two
consistencies. Why nothing is found in quadrupeds similar to the yolk,
nor in most vegetable seeds._ II. 1. _Eggs of frogs and fish
impregnated out of their bodies. Eggs of fowls which are not
fecundated, contain only the nutriment for the embryon. The embryon is
produced by the male, and the nutriment by the female. Animalcula in
semine. Profusion of nature's births._ 2. _Vegetables viviparous. Buds
and bulbs have each a father but no mother. Vessels of the leaf and bud
inosculate. The paternal offspring exactly resembles the parent._ 3.
_Insects impregnated for six generations. Polypus branches like buds.
Creeping roots. Viviparous flowers. Tænia, volvox. Eve from Adam's rib.
Semen not a stimulus to the egg._ III. 1. _Embryons not originally
created within other embryons. Organized matter is not so minute._ 2.
_All the parts of the embryon are not formed in the male parent. Crabs
produce their legs, worms produce their heads and tails. In wens,
cancers, and inflammations, new vessels are formed. Mules partake of
the forms of both parents. Hair and nails grow by elongation, not by
distention._ 3. _Organic particles of Buffon._ IV. 1. _Rudiment of the
embryon a simple living filament, becomes a living ring, and then a
living tube._ 2. _It acquires irritabilities, and sensibilities with
new organizations, as in wounded snails, polypi, moths, gnats,
tadpoles. Hence new parts are acquired by addition not by distention._
3. _All parts of the body grow if not confined._ 4. _Fetuses deficient
at their extremities, or have a duplicature of parts. Monstrous births.
Double parts of vegetables._ 5. _Mules cannot be formed by distention
of the seminal ens._ 6. _Families of animals from a mixture of their
orders. Mules imperfect._ 7. _Animal appetency like chemical affinity.
Vis fabricatrix and medicatrix of nature._ 8. _The changes of animals
before and after nativity. Similarity of their structure. Changes in
them from lust, hunger, and danger. All warm-blooded animals derived
from one living filament. Cold-blooded animals, insects, worms,
vegetables, derived also from one living filament. Male animals have
teats. Male pigeon gives milk. The world itself generated. The cause of
causes. A state of probation and responsibility._ V. 1. _Efficient
cause of the colours of birds eggs, and of hair and feathers, which
become white in snowy countries. Imagination of the female colours the
egg. Ideas or motions of the retina imitated by the extremities of the
nerves of touch, or rete mucosum._ 2. _Nutriment supplied by the female
of three kinds. Her imagination can only affect the first kind. Mules
how produced, and mulattoes. Organs of reproduction why deficient in
mules. Eggs with double yolks._ VI. 1. _Various secretions produced by
the extremities of the vessels, as in the glands. Contagious matter.
Many glands affected by pleasurable ideas, as those which secrete the
semen._ 2. _Snails and worms are hermaphrodite, yet cannot impregnate
themselves. Final cause of this._ 3. _The imagination of the male forms
the sex. Ideas, or motions of the nerves of vision or of touch, are
imitated by the ultimate extremities of the glands of the testes, which
mark the sex. This effect of the imagination belongs only to the male.
The sex of the embryon is not owing to accident._ 4. _Causes of the
changes in animals from imagination as in monsters. From the male. From
the female._ 5. _Miscarriages from fear._ 6. _Power of the imagination
of the male over the colour, form, and sex of the progeny. An instance
of._ 7. _Act of generation accompanied with ideas of the male or female
form. Art of begetting beautiful children of either sex._ VII.
_Recapitulation._ VIII. _Conclusion. Of cause and effect. The atomic
philosophy leads to a first cause._
I. The ingenious Dr. Hartley in his work on man, and some other
philosophers, have been of opinion, that our immortal part acquires during
this life certain habits of action or of sentiment, which become for ever
indissoluble, continuing after death in a future state of existence; and
add, that if these habits are of the malevolent kind, they must render the
possessor miserable even in heaven. I would apply this ingenious idea to
the generation or production of the embryon, or new animal, which partakes
so much of the form and propensities of the parent.
Owing to the imperfection of language the offspring is termed a _new_
animal, but is in truth a branch or elongation of the parent; since a part
of the embryon-animal is, or was, a part of the parent; and therefore in
strict language it cannot be said to be entirely _new_ at the time of its
production; and therefore it may retain some of the habits of the
parent-system.
At the earliest period of its existence the embryon, as secreted from the
blood of the male, would seem to consist of a living filament with certain
capabilities of irritation, sensation, volition, and association; and also
with some acquired habits or propensities peculiar to the parent: the
former of these are in common with other animals; the latter seem to
distinguish or produce the kind of animal, whether man or quadruped, with
the similarity of feature or form to the parent. It is difficult to be
conceived, that a living entity can be separated or produced from the blood
by the action of a gland; and which shall afterwards become an animal
similar to that in whose vessels it is formed; even though we should
suppose with some modern theorists, that the blood is alive; yet every
other hypothesis concerning generation rests on principles still more
difficult to our comprehension.
At the time of procreation this speck of entity is received into an
appropriated nidus, in which it must acquire two circumstances necessary to
its life and growth; one of these is food or sustenance, which is to be
received by the absorbent mouths of its vessels; and the other is that part
of atmospherical air, or of water, which by the new chemistry is termed
oxygene, and which affects the blood by passing through the coats of the
vessels which contain it. The fluid surrounding the embryon in its new
habitation, which is called liquor amnii, supplies it with nourishment; and
as some air cannot but be introduced into the uterus along with a new
embryon, it would seem that this same fluid would for a short time, suppose
for a few hours, supply likewise a sufficient quantity of the oxygene for
its immediate existence.