_Of Disease in general.--The nature of the Plague as a Disease
considered.--Of Contagion.--Whether the Plague is really Contagious
or not.--Medical History of the Distemper.--Inquiry into its
Immediate Causes, and whether an approaching Plague is indicated by
any visible Signs._
Hitherto we have considered the origin of the plague entirely in
a moral point of view. We have seen, that, in conformity to the
general opinion of mankind, it may reasonably be supposed to have
been inflicted upon mankind, the Jews particularly, for their
transgressions; that, having been once introduced, it has been
perpetuated, and spread from nation to nation, and that in proportion
to the degree of immorality of a certain kind prevailing through the
world. From this it is naturally to be inferred, that, were the human
race to live at peace with one another, to disperse themselves over
the face of the earth for the purpose of improving it by cultivation,
and were they to be contented with what the produce of each country
affords, there would be no plague among them. But we know that such
a reformation is not to be expected, and we must take the world as we
find it. The question then is, By what means shall individuals secure
themselves from being destroyed by a plague which shall happen to
invade any country; or how shall a person, already infected with it, be
restored to health? For this purpose let us begin with considering the
nature of disease in general, and of the plague particularly.
As to disease in general, physicians have differed very considerably
in their definitions; and, though many have been given, few seem to be
unexceptionable. That of Dr. Fordyce seems to be among the clearest
and most expressive. “Disease (says he) is such an alteration in the
chemical properties of the fluids or solids, or of their organization,
or of the action of the moving powers, as produces an inability or
difficulty of performing the functions of the whole or any part of the
system, or pain, or preternatural evacuation.” But as this definition,
however just, cannot be easily understood by such as are unaccustomed
to medical language, I shall attempt the following explanation of the
animal economy, and the diseases to which it is subject.
1. By nature our bodies are formed of certain solid and fluid parts,
operating upon one another in a manner of which we know but little.
Anatomists have described the structure of the human body and its
parts in a certain degree, but have always found themselves lost in an
inconceivable minuteness of texture. The whole structure of the human
body, visible and invisible, is called its ORGANIZATION.
2. This organized body is acted upon by certain powers residing in the
atmosphere, by which it becomes endowed with LIFE.
3. The operation of those powers upon a well organized body constitutes
that agreeable and vigorous state which we call HEALTH.
4. The operation of any other power, substituted in place of the
natural one, even upon a body perfectly organized, produces a state
very different from health; commonly attended with some uneasy
sensations, and which is called DISEASE. I say it is _commonly_
attended with uneasiness, but not always; for many persons within a few
hours, nay, a few minutes, of their death, have imagined themselves
quite recovered and well. To illustrate the meaning of what is said
of the substitution of any power instead of the natural one: It is
natural for man to breathe air of a certain quality; and while he does
so he continues in health; but let him breathe the vapour of burning
charcoal, or of fermenting liquor, mixed in considerable quantity with
the air to which he has been accustomed, and he will very soon find
himself diseased. Many other kinds of elastic fluids may be substituted
instead of the vapour just mentioned, all of which will in a short time
produce a disease in the most healthy man. The state of a diseased body
being very different from that of a sound one, the appearances are
consequently very different. The various appearances of disease in the
human body are called _symptoms_ of that disease, from a Greek word
signifying _appearance_.[44]
[44] “_Symptom_ (says Dr. Fordyce) is the Greek name for
_appearance_:” but, from the strict etymology of the word, it
ought rather to be translated _accident_. The universal consent of
physicians, however, has applied it to every appearance produced in
the human body by any distemper whatever.
5. A disease proves mortal only by the DISORGANIZATION of the body. By
disorganization I mean any considerable alteration in the structure of
the body, visible or invisible. The truth of this will appear from a
consideration of the method by which animals may be recovered, after
being to appearance dead by breathing the vapour of charcoal, or fixed
air in any other form, viz. by plunging them in cold water. In a cave
in Italy a continual stream of this kind of air issues from the ground.
It rises but a small way, so that a man may safely enter, because his
head is above the vapour; but, if he brings a small dog with him, the
animal, in consequence of breathing the pernicious fluid, falls down
as if dead, and would very soon die if left there. By throwing it into
a lake in the neighbourhood, (cold water of any kind would answer as
well) it recovers. In the dissection of some unfortunate people,
who have been killed by breathing this pernicious fume, a manifest
disorganization has been observed, viz. a rarefaction of the blood, and
too great dilation, or even rupture, of the small vessels.
6. A disease cannot always be cured by removing the cause which
brought it on: it is necessary also to repair the injury done to
the organization. This is exemplified in the case of the dog just
mentioned. Taking him out of the vapour is not sufficient for his
recovery, because the organization of the body is injured; the cold
water by contracting the vessels repairs the injury, and the cure
is completed. To the entire preservation of this organization it is
probably owing, that people have frequently recovered after being
thought dead for a long time.[45]
[45] Dr. Anthony Fothergill, in his prize dissertation upon the
suspension of vital action, quotes some experiments of Dr. Kite,
in which he was able to restore to life animals that had been
immersed in water for eight, ten or twelve minutes, though he
acknowledges that this operation, though performed with great
attention, often failed; while other animals, that had been longer
immersed, recovered spontaneously. He further adds, that if it be
not attempted before the convulsions of the animal cease, which
on an average of many experiments happens in about eleven minutes
and a half, it will not be sufficient to renew the vital motions.
But, “among the human species (says Dr. Fothergill) there are not
wanting well authenticated instances of spontaneous recovery at
an incomparably longer interval, and after every external mark of
life had disappeared. Such is the latent energy of the heart, that
it sometimes, after remaining several hours quiescent, renews on
a sudden the secret springs of life, surmounts the barriers of
the resisting blood, and restores circulation with all the other
functions. Hence the unexpected recoveries from death-like syncope
brought on by sudden terror, or great effusions of blood, even after
the funeral obsequies have been prepared. Hence some persons have
accidentally been brought to life, even after interment, by the rude
motion produced in sacrilegious attempts to wrest rings or bracelets
from the apparently dead body.”
Several surprising instances of the recovery of persons supposed to
be dead, even of the plague, are given by Fabricius Hildanus; to
one of which Dr. Fothergill seems to allude in the above quotation.
Hildanus relates, that in the year 1357, when the plague raged
violently at Cologne, a certain noble lady, by name _Reichmuth
Adoleh_, being seized with the disease, was thought to have died,
and was buried accordingly. Her husband, out of affection, would not
take off her wedding ring, which she happened to have on her finger.
The undertakers being acquainted with this circumstance, next night
came to the church where she was buried, opened the sepulchre, and
prepared to take off the ring; when to their utter astonishment she
began to raise herself up in the coffin. Struck with consternation
they fled in the utmost haste, leaving to the fortunate lady the
lantern with which they lighted themselves to the church, and by
means of which she now found out where she was, and after being
come to herself, returned to her own house. Here being known by her
voice, and the ring she wore, she found admittance, and by means of
a generous diet gradually regained her health; bringing her husband
afterwards three children, and surviving the accident many years.
A second instance no less remarkable is of a woman of the name of
_Nicolle Lentille_, who, being supposed dead of the plague, had been
thrown into a pit with a great number of the bodies of others, dead
of the same distemper. After lying there a whole night, she came to
herself in the morning, but neither knew at first where she was, nor,
when she did, could she find any means of escaping, or extricating
herself from the heap of dead bodies with which she was oppressed.
Being at a distance from any house, her cries were of no avail, and,
in the mean time, having taken no nourishment for four days, she was
so tormented with hunger that she eat part of the cloth which covered
her face. At last, after remaining twenty-four hours in this dreadful
situation, the pit being opened to bury some other person, she
exerted her utmost endeavours in calling for assistance, and at last
was heard by those who stood round. Being taken up and brought home,
she presently recovered, and lived several years after.
A third example is given by our author of one who, being carried to
a church to be buried, had his face previously sprinkled with holy
water by a priest. But this was no sooner done than he shuddered and
opened his eyes in a fright; on which he was carried home, recovered,
and lived eight years after. Other examples might be brought, but
these are sufficient to show what dreadful accidents may ensue from
early burials, and how cautious people ought to be in consigning
their friends and relations to the dust from whence they were taken.
7. When the organization of the body is injured, the action of the
natural powers themselves occasions uneasiness, and increases the
disease. The cure then is, to substitute instead of the natural
power, as far as possible, the action of some other power till the
organization is restored; after which the natural power must be again
allowed to act, or a disease of another kind will take place. This
may be exemplified in a consumption of the lungs; where, that part
being very much disorganized, pure air renders the disease worse; and
the sick are relieved by mixing with the common atmosphere such kinds
of air or vapour as would prove pernicious to people in health. But,
supposing this method to be successful, and the consumption to be
entirely removed, it is plain that the use of the pure atmosphere must
be resumed, or the impure air would bring on a disease in the same
manner as on a healthy person.
8. The body is wasted in the natural operations of life; part of
it passing off with the vapour of the breath, part by insensible
perspiration, &c. Hence it naturally tends to disorganization and
death, unless the waste be repaired.
9. This natural waste of the body is repaired, and health kept up, by
the food and drink taken into the stomach.
10. Hence arises another set of diseases; for as the reparation of the
waste, just mentioned, depends on the proper action of the stomach upon
the food, and the assimilation of the latter with the substance of
the body, it is plain that this operation depends both on the proper
quality of the food, and the sound state of the stomach itself.
11. The body is composed of solids and fluids of different kinds,
every one of which is subject to diseases peculiar to itself; but, by
reason of the connexion of the parts of the body with one another,
it is impossible that any one can be very much disordered without
affecting all the rest. As the bond of connexion, however, is in many
cases totally invisible to us, surprising instances frequently occur
of one part being affected in consequence of an injury done to another
very distant from it. This connexion between all parts of the body is
called SYMPATHY. Dr. Gardiner of Edinburgh, in his observations on
the animal economy, &c. says, that “the stomach is the principal seat
of many of the most remarkable sympathetic affections which happen in
valetudinary states of the body. Every disorder accompanied with severe
pain affects the stomach, whilst this viscus affects not only in its
diseased state every part of the system, but at other times the effects
of healthful stimuli applied to it are instantly communicated to the
rest of the body, as when we take food, wine, or medicine.” Dr. Darwin
in his Zoonomia informs us that the stomach is said to sympathize with
almost every part of the body; but Dr. Moore, in his medical sketches,
tells us that the _heart_ possesses a greater share of sympathy than
any other part in the body, and next to it the stomach.[46]
[46] Dr. Gardiner, in his observations above quoted, gives the
following curious anecdote. “An unmarried lady, of a healthy
constitution, has such a peculiarity in the structure of her nerves,
that, though she can, in general, bear strong odours as well as
most people, yet she cannot suffer a rose to be in her bosom, or
to hold it in her hand a few minutes, without becoming faint, and
having an inclination to vomit. Conserve of roses, rose-water, and
similar articles made from roses, have more powerful effects upon
her, and usually excite vomiting. Going into a room where any of her
companions are washing with rose-water, never fails to produce this
effect; nor does she recover of her indisposition in less than two
hours.”
12. The solid parts of the body are the bones, the muscles, brain
and nerves; the fluids are, the blood, and others produced from it.
The bones are known to every one; the muscles are the fleshy parts
throughout the whole body; and the nerves are a kind of cords seemingly
originating from the brain, and from thence accompanying the blood
vessels through all parts of the body.
13. Much has been disputed about what is to be accounted the primary
part of the body, on which all the rest depend; and one class of
disputants have arranged themselves on the side of the _blood_, and
the other on that of the _nerves_. The dispute is like one about
the beginning of a circle. It cannot be decided, because the blood
cannot act without nerves, nor the nerves without blood. I speak of
the human body, being aware that in some animals the position may be
controverted. The following is a concise state of the matter.
14. All the blood in the body passes through the heart; which has four
cavities; two called _ventricles_, and two _auricles_. These, from
their position in the body, are called the _right_ and _left_. The
right ventricle communicates with the right auricle, as does also the
left ventricle with the left auricle; but there is no communication
between the right ventricle and the left, nor between the right
auricle and the left. Through these cavities all the blood passes to
every part of the body, and returns from every part; but, as in the
former case, we are here at a great loss where to begin its motion;
for this is precisely to find the beginning of a circle. As we must
begin somewhere, however, we shall do so with the right ventricle of
the heart. This receives the blood returning from all parts of the
body, and propels it into the right ventricle; not the whole quantity
at once, for it cannot contain one half of it; but by degrees. The
auricle contracts as soon as it is full; and in the time that the
auricle fills, the ventricle contracts, so that it may be empty, and
ready to receive the blood from the auricle. By the contraction of
the right ventricle the blood is driven into the pulmonary artery,
and passes into the lungs. Here the artery branches into an infinite
number of small vessels much finer than hairs; and these again,
uniting into larger trunks, form at last the pulmonary vein, which
brings back the blood to the heart. The pulmonary vein is inserted
into the left auricle of the heart, which, as soon as it is filled
with blood, contracts, and expels the blood from it into the left
ventricle. From the left ventricle issues a large artery called the
_aorta_, which by its branches supplies the whole body with the vital
fluid. In all parts of the body the arteries divide themselves into
innumerable small branches, which terminate in veins equally small
as in the lungs; but it has been disputed whether the arteries and
veins actually join each other in the form of vessels, or whether the
arteries deposit the blood in small cells, from which the veins suck
it up. The dispute is of no consequence, nor can it be absolutely
decided, on account of the exceeding smallness of the vessels; though
the microscopical observations are rather favourable to the opinion
of a continuation of vessels. The veins from all parts of the body
unite into larger vessels, and these again uniting with one another,
form at last one very large vein called the vena cava, which opens
into the right auricle of the heart, from which the circulation goes
on as already described. The two ventricles of the heart, and all the
veins throughout the body, are furnished with a kind of valves, which
allow the blood to proceed in the way of circulation, but prevent its
returning in a contrary direction.
15. The lungs, through which all the blood in the body passes, receive
likewise the air which we draw in every time we breathe. They consist
of two large bodies called _lobes_; from their situation called the
right and left. The air is conveyed into them by the wind-pipe, called
also the _trachea_, and the _aspera arteria_. On entering the cavity of
the breast, the wind-pipe divides into two large branches called the
_bronchiæ_; one of which goes to the right and the other to the left
lobe of the lungs. By the further division and subdivision of these
vessels the lungs are filled with an innumerable multitude of little
tubes, terminating in exceedingly minute bladders or cells, which
are the final receptacles of the air sucked in when we breathe. Each
of these cells is surrounded with a kind of network of blood-vessels
exceedingly small, and consisting of very thin membranes; so that, in
passing through the lungs, the blood is exposed as much as possible to
the action of the air.
16. It is a matter of great importance to find out what is the use
of this exposure of the blood; and great disputes have taken place
concerning it. In former times it was supposed that the blood received
from the air a _vital spirit_, without which it would have been totally
incapable of performing its offices in the body. Later physiologists
endeavoured to explode this notion. Dr. Hales particularly, by shewing
that the circulation of the blood through the lungs might be continued
by inflating and contracting them alternately by the fumes of burning
brimstone, endeavoured to prove that the use of the air was only to
give the lungs an opportunity of dilating and contracting alternately,
by which means principally he thought the circulation might be carried
on. This continued to be the most common hypothesis as late as the time
of Dr. Huxham. It was however thought also that by the compression of
the air the blood was altered in its texture, its bulk, &c. Accordingly
Dr. Huxham tells us in the preface to his treatise on air and epidemic
diseases, that “air fit for respiration ought neither to be too hot,
nor very cold; for the use of the inspired air is to temperate the
blood, which would otherwise grow too hot, and putrefy, as is evident
from the experiment of the most excellent Boerhaave made in a hot
house; for, if the air is more hot, or even equally hot, as the blood
of any animal, it certainly soon dies.”[47]
[47] This certainly does not hold good if we suppose the heat of the
atmosphere to be indicated by a thermometer; for we are assured that
animals can live in a heat much superior to that which raises the
mercury to 97.
17. The modern discoveries in the composition of air, have tended
greatly to elucidate the use of this fluid in the lungs, and its action
on the blood in respiration. Dr. Priestly first determined it to be
what he terms a _phlogistic process_, i. e. a process by which the
parts of the blood no longer proper to be retained among the rest, or
at least some of them, are carried off. That _something_ is carried off
either from the lungs themselves, or from the blood circulating through
them, is evident; for the air which is taken into the lungs in a dry
state, comes out of them extremely moist, and loaded with vapour. An
essential change is also made in the nature of the air itself; for it
now assumes in a great measure the nature of what has been called fixed
air, or the fume of charcoal, or fermenting liquor, and thus becomes
unfit for being breathed a second time. This change is made by the
addition of some terrestrial substance to the pure atmosphere, which
the latter volatilizes and carries along with it.[48]
[48] The discoveries of modern chemists have determined that the
aerial fluid, termed _fixed air_ or _carbonic acid_, and which is
nearly the same with the vapour arising from fermenting liquor, and
is also largely contained in the fume of burning charcoal, is not
a simple but a compound substance; one part consisting of the pure
part of the atmosphere, or _oxygene_, the other of real charcoal. The
proportions, according to M. Chaptal, are 12,0288 parts of charcoal
to 56,687 of oxygen.
18. But, whatever may be _carried off_ from the blood, during its
passage through the lungs, something is certainly _added_ to it,
for the blood in the pulmonary artery is of a dark red, but when it
has undergone the action of the air in the lungs, and returns by
the pulmonary vein, it is then of a bright scarlet, which colour it
retains through all the arteries of the body, but loses it on its
return through the veins. This scarlet colour is communicated to blood
in all cases when exposed to the air; and Dr. Priestley has observed
that it is acted upon by the air even through a bladder; much more
then must it be so through those very thin membranes which form the
coats of the fine pulmonary vessels. What this subtile matter is which
the blood receives, shall be afterwards inquired into; at present it
is sufficient to take notice that it is absolutely necessary, for the
purposes of life, that the blood should pass through the lungs: for,
as Dr. Huxham observes, “we see neither nutrition, nor the motion of
the muscles, performed by any blood that hath not passed through
the lungs; this is observable from the coronary arteries[49] to the
ultimate ramifications of the aorta.” As the previous circulation
of the blood through the lungs therefore is absolutely necessary to
the growth and life of the body, and as the blood certainly receives
_something_ from the air, we must account this a proof, and no
inconsiderable one, that the air contains a _vital spirit_, which it
imparts to the blood in the lungs. But, before we proceed farther on
this subject, it is proper to take some notice of
[49] The name of the vessels by which the heart itself is supplied
with blood. These come from the aorta by the circuitous way of the
lungs.
19. _The nerves._ These, which constitute such a remarkable and
important part of the human body, are white cords, of a soft pulpy
substance, defended by a tough skin which goes along with them as far
as they can be traced. All the nerves either originate from the brain,
or terminate in it. The former doctrine hath been generally adopted,
and in conformity to that doctrine the following account of the nerves
is laid down. The brain is enclosed in the cavity of the scull, but not
without the intervention of two membranes, called the _dura_ and _pia
mater_, to prevent injury from the hard bones, as well as for other
purposes. The brain is divided into two lobes, the right and left. It
is composed of two different kinds of substance, the outermost called
the cortical, the innermost the medullary substance; the latter seems
composed of fine fibres. The whole of the medullary part of the brain
terminates in a substance called the _cerebellum_, very much resembling
the brain, but smaller. The cerebellum terminates in another substance
resembling the medullary part of the brain, called the _medulla
oblongata_. The cerebellum lies in the back part of the head, and
the medulla oblongata under it. The latter terminates in the spinal
marrow, extending from the lower and back part of the head to the lower
extremity of the back bone, and is enclosed in the hollow of that bone.
The nerves proceed from these four substances, viz. the brain, the
cerebellum, the medulla oblongata, and spinal marrow. As they pass to
all parts of the body they accompany the arteries, dividing with them
into innumerable small branches; but they do not return with the veins;
so that they seem not to contain any fluid which goes and comes, or
which circulates like the blood. The nervous fluid, if any such there
be, seems to move constantly one way, either to the brain or from it.
20. Hitherto we have noticed only things which are evident to our
senses, and which the industry of anatomists has abundantly evinced;
but now our subject renders it necessary to step aside a little into
the obscure regions of theory and conjecture. The muscles, as we have
formerly said, are the fleshy parts of the body; and by them all the
motions of the body are performed. The flesh is distributed into
distinct portions, each of which is enclosed in a membrane belonging
to itself. Each of these portions is a muscle, and each muscle has
a branch of an artery and the branch of a nerve belonging to it. On
both these the action of the muscle depends; for, if we cut the nerve
belonging to a muscle, it immediately loses all power of action; and
if we cut the artery which accompanies the nerve, it does the same. As
therefore the blood is found to receive _something_ from the air, and
as it loses this when passing through the arteries, and as the nerves
lose their power when the communication with the blood is cut off, it
seems extremely probable, that what is imbibed by the blood in the
lungs is taken up by the fine ramifications of the nerves, and is no
other than the immediate principle of life and sensation. Thus we will
establish a doctrine directly opposite to that commonly received; for,
instead of supposing that the nerves originate from the brain, we are
now led to suppose that they terminate in it. Instead of supposing that
the sensations originate in the brain, we will be led to suppose that
every sensation originates in the organ appointed for that sensation.
Thus we are conscious that our _eyes_, not our _brain_, are the parts
of our body which immediately perceive the light; our fingers, or
any other parts of the body, _feel_ what is applied to them; and of
consequence we have reason to believe that the _animal spirits_,
_nervous fluid_, or whatever we please to call it, proceed from the
surface of the body inwards to the brain, not outwards from the brain
to the surface of the body. The brain itself seems to resemble a large
collection or reservoir of water, in which the sensations, like so many
small streams from every part of the body, unite, and in which our
intellectual faculties reside in a manner totally inexplicable by us.
Thus far it seemed necessary to theorise, in order to form some idea,
however obscured, of the connexion between the nerves and our sensitive
and intellectual, or, if we please to call them so, our _spiritual_
faculties.
21. In consequence of this very intimate connexion between the blood
and nerves, it is easy to see that any injury done to the one may
very greatly affect the other; and that a very slight, nay, to us
imperceptible, change in the organization of either, may produce the
most grievous, and even incurable disorders throughout the whole body,
or in any particular organ. Let us now consider a little farther the
blood-vessels.
22. It hath been a question, whether in the structure of these vessels
nature hath observed an exact proportion. For instance, if the blood
passes by a kind of starts through four cavities, as we are assured
that it does, it seems natural to suppose that these four should be
exactly equal. This, however, hath been denied; and some, from its
accommodating the human frame to their theory, have fancied that
they saw the use of such disproportionate work. Dr. Huxham expresses
himself in the following words: “Nor doth the air only refrigerate the
blood, but, by preventing its too great ebullition, and condensing
it, hinders it from bursting the vessels. This indeed is of exceeding
great importance, if, with the very learned _Helvetius_, we suppose
the capacity of the right ventricle of the heart to be greater than
that of the left, and that the pulmonary arteries are larger than the
correspondent veins; for it thence follows, that the blood ought to
be considerably condensed by the inspired air, that an equal quantity
of blood may be received, in one and the same time, by the pulmonary
veins and left ventricle of the heart, that is thrown off from the
right ventricle, and through the more capacious pulmonary arteries.
This indeed many deny, asserting quite the contrary. It is necessary,
however, that the aorta should receive as much blood from the left
ventricle of the heart, as is thrown off from the right ventricle
through the pulmonary artery; and that in the very same and equal
time, or a fatal deluge would soon overwhelm the lungs, because the
contraction of each ventricle is made at one and the same time; we
always find therefore the aorta and pulmonary artery, in a natural
state, equal on this account; also the capacity of the ventricles ought
to be equal, that they may receive, in one and the same space of time,
equal quantities of blood,” &c.
If any thing farther is necessary upon this subject, we may still
observe, that if the blood were at all condensed by the air, it would
be so unequally, because the air is at some times much colder than at
others; and thus the disproportion of the cavities of the heart to
one another could not fail of producing the most disagreeable if not
fatal effects. We often see what terrible consequences ensue upon the
enlargement of any part of an artery near the heart; and these would,
sometimes at least, be felt by every individual.[50]
[50] But there is a still more egregious blunder, and this the more
surprising as it has been very general among physiologists, viz.
that when an artery branches into two the capacity of the branches
taken together is greater than that of the trunk. This would make the
whole arterial system one continued _aneurism_,[51] and, instead of
promoting the circulation of the blood, would in the most effectual
manner prevent it. In what manner an error so extraordinary in its
nature could pass the mathematical physicians of the last century,
I cannot imagine; but certain it is, that, in the year 1780 or
1781, the Edinburgh College were schooled on this subject by one of
their own students named _John Theodore Vander Kemp_, a Dutchman.
This gentleman found, by accurate mensuration, that when an artery
divides, if the diameters of the two branches are made the two
shorter sides of a right-angled triangle, the diameter of the trunk
will be the hypothenuse; and thus, as the areas of circles are to one
another in proportion to the squares of their diameters, the sum of
the areas of the two branches will be equal to the area of the trunk.
On looking into Blumenbach’s physiology, I find the same remark.
[51] An aneurism is a preternatural enlargement of an artery. The
blood stagnates in that place, and at length eats through the flesh
and skin.
It is true, indeed, that this objection will in some degree hold, even
though we suppose all the cavities of the heart to be equal, and the
capacities of the blood vessels to be perfectly uniform throughout the
whole body. For, if we suppose the blood to be at all condensed in the
lungs by the coldness of the atmosphere, it must undoubtedly follow,
that while passing from them it occupies less space than before it
arrives at them. Hence the pulmonary vein, the left auricle of the
heart, the left ventricle, the aorta, and all the rest of the arteries
for a considerable way, must be comparatively empty, even though
they receive as much fluid as fills the vena cava, right auricle and
ventricle of the heart, and pulmonary artery. The equality which ought
to prevail in the system, and which indeed cannot be dispensed with,
can only take place in those remoter branches of the arteries in which
the blood has reassumed its former state of dilation or rarefaction.
23. If we consider this matter attentively, we shall find it not a
little mysterious. Every time we breathe out the air we have sucked
into our lungs, a considerable quantity of moist vapour is breathed
out along with it; but it has been proved by undeniable experiments
that the emission of aqueous vapour from any substance cools it in
proportion to the quantity of vapour emitted. Every breath we draw,
then, cools the lungs, and consequently the blood, to a certain degree,
and, as the number of times that we breathe in a day is exceedingly
great, the cold produced by the evaporation ought to be in proportion.
But we see that, notwithstanding all this cooling, whether we breathe
cold air or hot air, the temperature of the body remains still the
same. The air then, though constantly carrying off the heat of the
body, does not cool it in the least by its action on the lungs. The
only possible way of solving this apparent contradiction is, by
supposing that the air, when acting upon the blood in the lungs, leaves
precisely as much heat as it carries off, and therefore, though we
breathe ever so long, we cannot by this means become either hotter or
colder.
24. To illustrate this subject, we might now enter into an inquiry
concerning the origin and cause of animal heat; but this will be
touched upon hereafter. We shall here only take notice that the heat of
the body is almost universally allowed to proceed from the lungs. It
has likewise been demonstrated, that the air does in fact contain an
incredible quantity of heat, even when it appears to us to be extremely
cold. A certain proportion of this heat is separated from it every time
we breathe; and if, either by the mixture of other fluids with the air
we breathe, or by any change in the organization of the body itself,
a greater or smaller proportion of heat should be communicated to the
blood, disease must ensue.
25. To sum up then what has been said concerning the blood and nerves:
The whole mass of fluid passes from the right side of the heart to the
lungs. In the lungs it receives from the air something[52] necessary
to the functions of life and sensation, and purifies itself from
those matters which might prove pernicious. From the lungs it passes
to the left side of the heart, and thence through the whole body. In
its passage through the body, it is accompanied with nerves, which,
taking up from the arterial blood that _vital spirit_ received from
the air, convey it to all the organs of motion, of sensation, and to
the brain, where the whole powers of perception being united form our
_intellectual faculties_, and, as far as our senses can perceive,
the human spirit itself. The blood, thus deprived of its spirit, is
collected from all parts of the body by the veins, and returned to the
right side of the heart, from whence it is again sent to the lungs,
and the process carried on as before. This hypothesis concerning the
peculiar function of the nerves I first inserted in the Encyclopædia
Britannica, second edition, under the article BLOOD, in the year 1778.
It has been since continued in the third Scots edition, and from thence
into the Irish and American editions.
[52] It seems now to be proved beyond a doubt that this
_something_ so long unknown is that fluid called by Dr. Priestley
_dephlogisticated air_, and by Lavoisier _oxygen_.
26. It has already been observed, that the body is subjected to a
continual waste. One source of this waste is the breath, by which a
considerable part passes off in vapour. A great quantity also passes
off by the pores of the skin; frequently in a perceptible liquid called
_sweat_, but oftener in an invisible vapour from all parts of the body,
called _insensible perspiration_. The latter has been thought to be the
great source of waste to the human body; and it is certain, that if any
person in health be weighed when he rises in the morning, he will be
found considerably lighter than when he went to bed. The loss of weight
in this case proceeds not only from the pores of the skin, but from the
lungs; but though physicians have made a general allowance for both
these, I have not heard of any experiment by which we can determine
how much passes off by the one, and how much by the other, nor indeed
does it appear easy to make such an experiment. Galen plainly overlooks
the perspiration from the lungs entirely. “This excrementitious vapour
(says he) is expelled through small orifices, which the Greeks call
pores, dispersed all over the body, and especially over the skin,
partly by sweat, and partly by insensible perspiration, which escapes
the sight, and is known to few.” Sanctorius, and the succeeding
writers, have classed both together indiscriminately; allowing the
discharge to be so great, that if eight pounds of aliment be taken in,
five of them pass off in this manner. In a system of anatomy, published
at Edinburgh in 1791, the author says, that the discharge by the skin
“is even much larger than this (the discharge from the lungs we may
suppose) since it not only throws off a quantity of the aliment, but
likewise what is added to the blood by inhalation, which, entering
often in a very considerable quantity, is thus again expelled.” The
same author likewise says, that the “perspirable matter from the skin
is principally water,” and that it issues in such quantity as to be
seen in subterraneous caverns evidently flying off from the surface of
the body like a dense vapour. But other physiologists, particularly Dr.
Blumenbach, inform us, that the matter of insensible perspiration is
quite similar to the discharge from the lungs, particularly containing
a great quantity of fixed air. The same account is given in Chaptal’s
chemistry, on the authority of Messrs. Milly and Fouquet. This may
be looked upon as a valuable discovery, especially in conjunction
with that related by Drs. Beddoes and Girtanner, viz. that the flesh
of animals contains a quantity of oxygen. Dr. Girtanner obtained a
quantity of this air from the raw flesh of animals, and says that it
may be repeatedly obtained by exposing the flesh to the atmosphere, and
distilling with a heat of 60 or 70 degrees of Reaumur’s thermometer
(something below that of boiling water.) Hence it is natural to
conclude, that, as the discharge from the lungs purifies the blood
from its useless parts, so does the insensible discharge from the skin
purify the solid parts from those particles which are no longer useful.
The probability of this also becomes greater by considering, that in
diseases, when the quantity of matter to be thrown off is very great,
the skin becomes foul, the teeth furred with black sordes, &c. all
which disappear as soon as the quantity of the offensive particles is
reduced to its natural standard. As to any considerable quantity of
aqueous vapour being discharged this way, unless in case of sweat, it
does not seem probable; for in such a case our clothes would always
be moist; and in the night time the accumulation of moisture would
certainly be perceptible. The sweat is entirely of a different nature
from the insensible perspiration, and blood and even _sand_ has been
known to issue through the skin along with it. (_See the Anatomical
System above quoted._)
27. This very considerable waste of the body is repaired by the aliment
taken into the stomach. In the mouth it is mixed with a considerable
quantity of the liquid called _saliva_, and in the stomach with another
called the _gastric juice_, with which that organ always abounds. From
the stomach it passes into the intestines, where it is mixed with other
two fluids; one called the _pancreatic juice_, the other the _bile_.
This last is of a yellow colour, and is sometimes produced in enormous
quantities, insomuch that Dr. Wade, in his account of the fevers in
Bengal, mentions some patients who have voided by stool half a gallon
of bilious matter in one day.
28. In the stomach principally the aliment undergoes a certain change
called _digestion_, by which it becomes capable of being converted into
the substance of the body. Much has been inquired and disputed, to no
purpose, about the nature of this change, and how it is effected. One
party has declared for _attrition_; a second for _putrefaction_; a
third for _heat_; a fourth have supposed that our meat was digested by
_chewing_; as if, like the lobster, people had teeth in their stomach!
and, lastly, some learned moderns, after much pains and trouble, have
found out that it is digested by _solution_. Dr. Moore has summed up
the discoveries concerning digestion in the following words: “The
food, being previously divided and blended with the saliva and air by
mastication, (chewing) is swallowed, and meets in the stomach with
the gastric juice, whose dissolving power, assisted by the natural
heat of the place, is the principal agent in digestion. The process is
completed by the pancreatic juice and bile, the nutritious parts of the
food being by this process converted into chyle for the support of the
body, and the grosser parts thrown out.”[53]
[53] Moore’s Medical Sketches.
29. The inside of the stomach and intestines are full of the mouths of
innumerable small vessels, which continually suck up from the aliment,
as it passes downwards, the finer parts, in form of a white liquid,
called _chyle_; and from the whiteness of their colour the vessels have
the name of _lacteals_, from the Latin word _lac_, milk. After passing
through the substance of the stomach and intestines, and running along
the membrane called the _mesentery_, to which the intestines are
attached, the lacteals unite in a large reservoir called the _thoracic
duct_; and this again opens into a large vein on the left side, called
the _subclavian_, which conveys the blood from half the upper part of
the body; soon after terminating in the vena cava, by which the chyle
is conveyed to the heart, thence to the lungs, and so on in the common
course of circulation. The conversion of the chyle into blood is called
the process of _sanguification_.
30. The blood, thus formed out of the aliment we swallow, is not one
uniform fluid like water, but composed of three distinct substances;
one, which gives it the red colour, and seems to be composed of little
round globules; another, quite colourless, but of a viscid nature,
and which very soon coagulates, called the _lymph_; and a third, of a
yellowish colour, and retaining its fluidity much longer, called the
_serum_. A remarkable property of this last fluid is, that air can act
through it upon the blood; for Dr. Priestly found that a portion of
black blood assumed a bright, florid colour from the air, even though
covered with serum an inch deep. When blood is drawn, the red globules
are detained by the lymph which coagulates, and both together form
the red mass called _crassamentum_; the serum remaining fluid, and
retaining its name.
31. Besides these fluids, the blood either invisibly contains, or
is capable of being converted into, a great many others; for all
the fluids in the body are separated from it, and all of them, the
bile only excepted, from the arterial blood, before it has lost that
portion of its spirit which it imbibes from the air. When a fluid is
to be secreted, sometimes it is done only by an infinity of small
vessels branching off from the arteries, and depositing the liquids
which pass through them in particular places; and such are the fluids
which moisten the inside of the body, and which are carried off by the
breath, or by sweat. But this separation does not by any means hinder
the artery from terminating in its usual way in a vein, for in no case
is the whole substance of the blood converted into any other liquid;
all of them appear to be contained in it. But the greatest number of
fluids are separated by means of certain substances called _glands_.
These are small round or oval shaped bodies; each of them enclosed in
a membrane or skin which separates it from the other parts, and each
furnished with a small tube called the _excretory duct_, through which
the liquor separated in the gland passes to its place of destination.
Each gland has also an artery and nerve, and a vein to bring back the
blood after it has parted with the fluid intended to be separated. The
bile is separated in the liver from the blood of a large vein called
the _vena portarum_, formed by the union of some of the veins of the
intestines and mesentery. This vein branches out through the liver like
an artery, terminating in other veins, which at last bring back the
blood to the heart.
32. As the human body is thus furnished with an apparatus for
separating and carrying off, it is also furnished with one for
absorbing or taking in. All the inward parts of the body are moist;
and the moisture is furnished by the small vessels above described,
and which separate part of the lymph from the blood. By such continual
separation the cavities of the belly, breast, brain, &c. would soon
be filled with liquid, were not some means provided for carrying it
off as fast as it is formed. The means in question are a set of small
vessels called _lymphatics_. These “arise from the internal surface of
the breast, belly, and every cavity of the body; they also overspread
the whole external surface of the body, and large lymphatic vessels
are usually found close to the large blood vessels of the extremities,
besides those small superficial ones which lie above the muscles in the
cellular membrane (the fat or rather the membrane containing it.) The
large viscera generally have two sets of lymphatics, one lying on the
surface of the viscus, and the other accompanying the blood vessels
belonging to it. The faculty of absorption, though refused to the
lymphatics, was ascribed by many anatomists to common veins, and this
opinion continued to prevail in some degree, until Hunter and Monro
totally overturned it, exploding at the same time the notion that any
of the lymphatics are continuations of arteries, and establishing,
beyond a doubt, that all are absorbent vessels.”[54] All the lymphatics
terminate in the thoracic duct; so that the liquid separated by the
_exhalant arteries_ (so the vessels are termed by which that fluid is
separated) is again mixed with the blood, and again performs the same
offices.
[54] Moore’s Medical Sketches.
We have now taken a review of the several parts of the human body,
slight and superficial indeed, but such as the limits of this work
would allow, and sufficient to furnish to those entirely unacquainted
with medical matters some general ideas on the subject. We have seen
that the body, in general, consists principally of four great parts,
the blood-vessels, the lymphatic vessels, the nerves, and the muscles.
Besides these we enumerate the glands and membranes; the former being
nearly allied to the blood-vessels, the latter _apparently_ to the
nerves. The bones, having no concern with our present inquiry, are not
taken notice of. The stomach and intestines, being principally composed
of muscular fibres, nerves, and blood-vessels, must be considered
as belonging to these departments. Each of these large divisions
has obtained the name of _system_; and even the subdivision of the
blood-vessels into arteries and veins. Thus the arteries of the body,
taken collectively, are called the _arterial system_; the veins the
_venous system_; the brain and nerves the _nervous system_; the muscles
the _muscular system_; the lymphatics the _lymphatic system_; and the
glands the _glandular system_; &c. These appellations have been given
for the sake of distinctness and perspicuity, but they have had a bad
tendency. Insignificant disputes have arisen concerning the superiority
of one system to the other, and which is to be accounted the _primum
mobile_ of the body. By observing also the _general_ structure of the
body in a more full and ample manner than that of the parts which
compose it, physicians have been apt to generalize too much in their
theories, and to fancy that from a few obvious laws they might be able
to explain the phenomena of disease in almost every possible variety.
To illustrate this, let us take the blood for an example. This to sight
appears an homogeneous fluid; and Boerhaave and others have ascribed
diseases to some defect or bad quality of the blood. But this fluid
consists of three parts, each, as far as we can perceive, essentially
distinct from the other; viz. the lymph, serum, and red globules.
As each of these happens to be diseased, the cure must be different;
or if two happen to be diseased, the medicines must still be varied.
But, besides these general diseases arising from what, like the blood,
is common to the whole body, each component part of the body has an
arterial system, a venous system, a nervous and lymphatic system, &c.
belonging to itself; all of which, though dependent on the body at
large, have yet laws of their own, in consequence of which any one of
them may be considerably diseased without much affecting the general
system; and this constitutes what is called _local_ disease. Again:
The parts of the body are so connected with one another, that the
disease of one may show itself in another; or it may affect the whole
body in such a manner as to produce a general disease; though Dr.
Rush considers this last, at least from injuries of the viscera, as a
rare occurrence;[55] but we certainly know that general diseases are
very often followed by evident diseases of particular organs; and in
these cases it is impossible to say whether the general disease did
not begin, though imperceptible to us, in that very organ in which
we suppose it to terminate when the local disease was come to such
an height as to be evident to our senses. In some cases it is plain
that local injuries will bring on most violent diseases of the whole
system. Thus a local inflammation of the end of one of the fingers,
by physicians called a _paronychia_, has been known to induce a most
violent fever, nay, even to occasion death. These violent symptoms
end as soon as the suppuration is completed; so that, were it not for
the excessive pain of the inflammation, we might be apt to suppose
that the fever terminated in the suppuration, whereas it evidently
was occasioned by the local disease, or the tendency of the part to
suppurate; the pain and inflammation being necessary preliminaries.
Again: When an intermittent fever is said to terminate, or to be
followed, by a hardness of the liver, we do not certainly know whether
an original disease of the liver might not have been the cause of
the intermittent. From a consideration of all these things, viz. the
extreme diversity of parts which compose the human body, the ultimate
invisibility of the structure of each, the incomprehensible manner
in which they are united, the equally incomprehensible dependence
they have upon one another in some cases, and independence in others,
the numerous laws by which they are governed, and which must be very
much unknown to us, the invisible and incomprehensible nature of the
powers which act upon them, &c. &c. I say, when we consider all these
things, the boldest theorist must be humbled when he attempts to
account for the phenomena of disease in any one instance. The excessive
difficulty in which we are involved is beautifully described by Dr.
Ferriar when speaking of hysterics; and obstacles equally insuperable
by our theories will undoubtedly be met with in any other distemper.
“We are ignorant (says he) by what laws the body possesses a power of
representing the most hazardous disorders, without incurring danger;
of counterfeiting the greatest derangement in the circulating system,
without materially altering its movements; of producing madness,
conscious of its extravagances; and of increasing the acuteness of
sensation by oppressing the common sensorium. In hysterical affections
all these appearances are excited, which are incompatible with the
reasonings of every system-maker who has yet endeavoured to explain the
inexplicable. Nature, as if in ridicule of the attempts to unmask her,
has, in this class of diseases, reconciled contradictions, and realized
improbabilities, with a mysterious versatility, which inspires the true
philosopher with diffidence, and reduces the systematic to despair.”
[55] Medical Inquiries and Observations, vol. iv, p. 133.
Notwithstanding all these difficulties, however, physicians have
theorised, and that with such animosity, as if all the arcana of nature
had been laid open to every professor who thought proper to invent or
new-model a system; though the constant succession of theories might
certainly have shown them the vanity of such attempts. Some of these we
must now consider.
Medical theorists have exerted their greatest abilities in explaining
the nature of those general diseases affecting the whole body,
denominated _fevers_; and which are likewise called _acute_ diseases,
from the violence with which they sometimes attack, and the rapidity
with which they run through their course. Dr. Fordyce says, that
fever will sometimes kill in _five minutes_ from the first sensation
of uneasiness. Ancient physicians have described a number of fevers,
which they supposed to be of different species, and accordingly have
distinguished by different names. Modern system-makers have added
to the number; so that a bare detail of the names which they have
given to their divisions and subdivisions, would constitute a very
formidable catalogue; but the latest practitioners are decidedly of
opinion that there is but one kind of fever, varying itself according
to circumstances. Dr. Rush declares himself of this opinion in
the most express and positive terms. “There is (says he) but one
fever. However different the predisposing, remote or exciting causes
may be, ... still, I repeat, there can be but one fever.... Thus
fire is an unit, whether it be produced by friction, percussion,
electricity, fermentation, or by a piece of wood or coal in a state of
inflammation.”[56]
[56] Vol. iv, p. 133.
“I have said that there is but one fever. Of course I do not admit
of its artificial division into genera and species; a disease which
so frequently changes its form and place, should never have been
designated, like plants and animals, by unchangeable characters....
Much mischief has been done by nosological arrangements of diseases.
They erect imaginary boundaries between things which are of an
homogeneous nature.... They gratify indolence in a physician, by fixing
his attention upon the name of a disease, and thereby leading him to
neglect the varying state of the system, &c.”[57]
[57] Ibid. p. 149.
So much then having been said and written upon the disease in question,
one might be apt to suppose that the nature of fever would have
been thoroughly investigated, and its causes explained in the most
satisfactory manner, long before this time. Instead of this, however,
we find it still like a word which every body uses, and nobody
understands. Dr. Fordyce, who has lately written a treatise on the
subject, endeavours to prove that there is not any single symptom from
the existence of which we can certainly determine the presence of this
disease. “Fever (says he) has obtained its name in Greek, Latin, Arabic
and Persian, principally from the idea of heat: _pur_, in Greek fire;
_febris_ in Latin, from _fervere_, to burn,” &c. This idea, he goes
on to demonstrate, is erroneous; as the body of a feverish patient
frequently sinks the thermometer below the natural standard; while the
patient sometimes finds himself cold when the thermometer shows him
to be really hot, and hot while the same instrument shows him to be
cold. Neither is cold, followed by heat, a certain indication of the
presence of fever, as many fevers begin without any previous sensation
of cold. Frequency of the pulse also is no certain sign; and having
discussed this last symptom he concludes thus. “If we examine the
restlessness, anxiety, state of the tongue, head-ach, or any other of
the symptoms which often take place in fever, we shall find that they
also may be present when there is no fever, and absent in a patient
afflicted with this disease; and therefore we cannot allow that there
is any pathognomic symptom of fever.”[58] Dr. Rush declines giving
any definition of fever;[59] but, with all due deference to these two
very experienced physicians, we must account such extreme scepticism
altogether erroneous. If fever cannot be defined, it cannot be
described; for a _definition_ is no other than a short _description_.
If again there be no single symptom by which the presence of fever
can be known, it is impossible that there can be any _combination_
by which it can be known, any more than we can form an unit by any
combination of cyphers. In fact Dr. Fordyce himself is at last obliged
to acknowledge that there is a certain symptom with which fever
_generally_ begins; and, by his insisting upon it in various parts of
the work, we must certainly be induced to suppose that it was by this
sign principally that he determined whether his patients had a fever
or not. “The first appearance (says he) which generally takes place is
uneasiness and restlessness; a general uneasiness, the patient feeling
himself ill, but incapable of fixing on any particular part of the
body. This uneasiness affects the mind at the same time. Perhaps in
this case it is the mind that is first affected.... Along with this
uneasiness there is a restlessness, the patient wishing to change his
place or posture frequently; the mind cannot likewise rest upon one
object; it often wanders from one to another subject. At the same time
there is a feel of weariness which resists the disposition in the
patient to change his place and posture, and resists the disposition
of the mind to alter the object of its attention, rendering the wish
for such changes ineffectual. With these arises an actual inability of
exerting the muscular powers, or performing any of the functions of the
body; and also an actual inability of exercising the great faculties of
the mind, the powers of perception, memory, arrangement of ideas, and
of the judgment, in the same degree that they existed in health. The
degree in which these take place is extremely different in the attacks
of different fevers; but these appearances are _very rarely_ absent,
although indeed they may also happen in other diseases.”
[58] A _Pathognomic_ symptom is one which being present _certainly_
indicates the presence of a disease, and being absent, the contrary.
[59] Vol. iv, p. 123.
Dr. Rush accounts the lassitude with which fever begins, one of the
transient phenomena of it; and this with other phenomena he calls
_symptoms_. Such as are more permanent and fixed, and which by other
writers have been reckoned different species, he calls _states_; and of
these he enumerates forty. Such as have any relation to the plague are
as follow.
I. The MALIGNANT state, known by attacking frequently without a
chilly fit, is attended with coma, a depressed, slow or intermitting
pulse, and sometimes by a natural temperature or coldness of the
skin.... This depressed state of fever more frequently when left
to itself terminates in petechiæ, buboes, carbuncles, abscesses and
mortifications, according as the serum, lymph, or red blood, is effused
in the viscera or external parts of the body.
2. The SYNOCHA, or common inflammatory state; attacking suddenly with
chills, succeeded by a quick, frequent and tense pulse, great heat,
thirst, and pains in the bones, joints, breast or sides.
3. The BILIOUS state of fever; known by a full, quick and tense pulse,
or by a quick, full and round pulse without tension, and by a discharge
of green, dark coloured or black bile from the stomach and bowels. This
state sometimes assumes the form of an hectic; the patient feels no
pain in his head, has a tolerable appetite, and is even able to sit up
and do business.
4. The TYPHUS state; known by a weak and frequent pulse, a disposition
to sleep, a torpor of the alimentary canal, tremors of the hands, a
dry tongue, and, in some instances, a diarrhœa. Sometimes it assumes
symptoms of synocha on the eleventh, fourteenth, and even twentieth
days. The common name of this state is the _nervous_ fever.
5. Intermissions, or the INTERMITTING and REMITTING states, occur
most distinctly and universally in those which partake of the bilious
diathesis.
6. The SWEATING state occurs not only in the plague, but in the yellow
fever, small pox, pleurisy, rheumatism, hectic and intermitting states.
7. The FAINTING state; occurring in the plague, yellow fever, small
pox, and some states of pleurisy.
8. The BURNING state. This is attended not only with an intolerable
sensation of heat in the bowels, but with a burning sensation excited
in those who touch the patient’s skin. It occurs mostly in the
remitting fevers of Asia.
9. The CHILLY state differs from a common chilly fit by continuing four
or five days, and to such a degree that the patient frequently cannot
bear his arms out of bed. The coldness is most obstinate in the hands
and feet. A coolness only of the skin attends in some cases, which is
frequently mistaken for an absence of fever.
10. The INTESTINAL state; including the cholera morbus, diarrhœa, and
cholic.
11, 12, 13, 14, 15. The APOPLECTIC, PHRENETIC, PARALYTIC, LETHARGIC and
VERTIGINOUS states.
16. The ERUPTIVE state; including the small pox, measles, and other
exanthemata of Dr. Cullen.
17. The HÆMORRHAGIC state; known by fluxes of blood from various parts
of the body.
18. The CONVULSIVE or SPASMODIC state. Convulsions are frequently
attendant on the malignant state of fever.
19. The CUTANEOUS state; attended with various eruptions on the skin,
particularly _petechiæ_.
These include the most remarkable varieties described by physicians
as different species. From the subsequent account of the symptoms of
the plague, it will appear that this single distemper monopolises,
as it were, the symptoms, at least the most dangerous and terrible,
belonging to them all. Those nosologists therefore who suppose the
states of fever above described to be different species, instead of
saying that the plague belongs to one kind of fever, ought to say
that it is a complication of a great many different kinds. But here a
question arises: Do all the varieties of fever just now described, or
do all the other fevers described by different authors, include all the
different modes by which the plague makes its attack? If so, then we
know that the plague really partakes of the nature of fever, or may be
accounted the highest degree of it. This is the opinion of Dr. Rush;
for in his 4th vol. p. 153, he considers the different inflammatory
states of fever, according to their strength, in the following order.
1. The plague. 2. The yellow fever. 3. The natural small pox. 4. The
malignant sore throat, &c. To this I can have but one objection,
and to me it appears insuperable; viz. that the plague frequently
destroys without any symptom of fever; and, if so, we must certainly
account it a distemper of another kind. To decide this matter, let
us compare the symptoms of the most violent fever with what happens
in times of violent pestilence. We can scarce imagine a fever more
powerful than that which destroys in five minutes, and the following
is the description of it from Dr. Fordyce. “When the first attack of
fever has been fatal, it has been classed among sudden deaths, and
all of these have been very erroneously called apoplexy, or syncopy
(_fainting_.).... When the attack is fatal, it sometimes kills in five
minutes, sometimes it requires half an hour, seldom longer than that
time. While the patient is yet sensible, violent head-ach with a great
sense of a chilliness takes place, the extremities become very cold,
and perfectly insensible; there is great prostration of strength,
so that the patient is incapable of supporting himself in an erect
posture; he becomes pale, his skin is of a dirty brown, and he is soon
insensible to external objects; the eyes are half-open, and the cornea
somewhat contracted. If the patient goes off very soon, the pulse is
diminished, and at last lost, without any frequency taking place, but
if it be longer before he dies, the pulse becomes excessively small
and frequent; all the appearances of life gradually subside, and
the patient is carried off. Of this the author has seen instances,
sometimes at the first attack, oftener in the returns of the disease,
although very few.”
This no doubt is very terrible, and no plague whatever can exceed it.
Indeed, when _death_ is the termination, it signifies little what the
_disease_ is called. But the question is not whether fever or plague is
the most dreadful, but whether they are the same. Now, from the above
description, it is plain that fever never kills without some warning.
In the present instance, head-ach and chilliness give a certain, though
short, warning of the ensuing catastrophe; but, in violent plagues, Dr.
Sydenham informs us, that people have been suddenly destroyed as if by
lightning. Dr. Guthrie assures us that in the last plague at Moscow
he has seen soldiers drop down suddenly as if they had been struck
by lightning, or by a musket ball; yet some of these recovered by
bleeding and proper management; but it is certainly not unreasonable
to suppose that many, who were not thus taken care of, perished. Dr.
Hodges speaks of the contagion of the plague in the most energetic
terms. He says, “it is so rare, subtile, volatile and fine, that it
insinuates into, and resides in, the very pores and interstices of
the aerial particles. It is said to be of a poisonous nature also,
from its similitude to the nature of a poison, so that they seem to
differ in degree only; for the deadly quality of a pestilence vastly
exceeds either the arsenical minerals, the most poisonous animals or
insects, or the killing vegetables; nay, the pestilence seems to be
a composition of all the other poisons together, as well as in its
fatal efficacies to excel them.... The contagion of the plague is
more active than lightning, and in the twinkling of an eye carries to
a distance putrefaction, mortification and death. As for the manner
whereby it kills, its approaches are generally so secret, that persons
seized with it seem to be fallen into an ambuscade or a snare, of which
there seems to be no suspicion.... In the plague of 1665, as in many
others, people frequently died without any symptoms of horror, thirst,
or concomitant fever. A woman, who was the only one left alive of a
family, and in her own opinion in perfect health, perceived upon her
breast the pestilential spots, which she looked upon to be the fatal
_tokens_; and in a very short space died, without feeling any other
disorder, or forerunner of death.... A youth of a good constitution,
after he had found himself suddenly marked with the tokens, believed at
first that they were not the genuine marks, because he found himself
so well; yet he was dead in less than four hours, as his physician had
prognosticated. A fever, however, did for the most part show itself,
and was always of the worst kind. Sometimes it seemed to resemble a
quoridian, sometimes a tertian; there never was a total cessation, but
every exacerbation was worse than before.” In like manner the author
of the Journal of the Plague Year informs us that many, supposing
themselves, and supposed by others, to be in good health, would
suddenly find themselves seized with great sickness, crawl to a bench,
and instantly expire. “Many (says Dr. Hodges) in the middle of their
employ, with their friends and other engagements, would suddenly fall
into profound, and often deadly sleeps.”
It is needless to multiply examples: the above are sufficient to
show that the plague, when in its most violent state, kills suddenly
and imperceptibly, and that like the bite of a vampire,[60] without
producing any sensible disorder. In a state somewhat inferior, it
excites the most malignant fevers; in one still inferior it produces
fevers of a milder nature, and so on until we find it so mild, that
those infected with it are not even confined to their bed. In all
this inquiry, however, we find the secrecy and invisibility of the
pestilence, so often mentioned in scripture, still confirmed. Other
distempers may “waste openly at noon-day,” but this always “walks in
darkness.”
[60] The vampire is a kind of bat, of a very large size, met with
in some parts of South America and in the East Indies. This vile
creature delights in human blood, and often attacks people in the
night time in the most insidious manner. A late traveller relates
that at Surinam he was bit by one of them, which sucked so much of
his blood that in the morning he found himself exceedingly weak and
faint. He felt no pain, nor was sensible of the injury in any other
way. The vampire commonly attacks the great toe, making a wound
so exceedingly small that the person is not awaked by it; it then
sucks till gorged with blood, and, lest the patient should awake, it
keeps fanning him all the while with its large wings, the coolness
of which, in that hot climate, promotes sleep. In this manner some
are said to have been destroyed. Captain Cook relates an humourous
anecdote of one of his sailors, who being ashore at New Holland, and
having wandered a little way into the woods, returned in a fright,
crying out that he had seen _the devil_! Being asked in what shape
Satan had appeared, he answered, “He was about the size of a _one
gallon keg_, and very like it; and if I had not been _afear’d_, I
might have touched him.” It was a vampire. The man, notwithstanding
his fright, had not exaggerated its magnitude. People, though
mistaken and terrified, are not to be disbelieved in every part of
their relation.
In one of the inferior stages of this distemper the body is affected
with those eruptions named buboes and carbuncles. Dr. Patrick Russel,
in his treatise on the plague at Aleppo, divides the symptoms of the
distemper into six classes. In the first there were no eruptions,
and all the patients of this class died. In the second, and all the
rest, there were buboes and carbuncles. But, in the latter of these
especially, it is worthy of remark, that they appear neither as
a suppuration, nor as a common mortification, but like the eschar
formed by a caustic, which can scarcely be cut by a knife. This
appearance is not to be met with in any other disease. In many there
are mortifications of various parts of the body, but all these are
soft, and seemingly corruptions of the flesh. When a person dies of any
ordinary distemper, the flesh soon corrupts and dissolves, but there
is no example of its turning to a hard eschar like that made by a hot
iron, or the caustic with which issues are made. This shews not merely
a cessation of life, but the operation of some very active power in the
body, like fire, tending to destroy the texture of it entirely, and to
reduce it to a cinder. This power seems also to operate internally in
the fleshy parts; for when the bodies of those were opened who died
with the _tokens_, as they are called by Dr. Hodges, upon them, the
mortification was always found much larger inwardly than it appeared
to be on the outside. The tokens themselves are by Dr. Hodges called
“minute distinct _biasts_, which had their origin from within, and
rose up in little pyramidal protuberances, sometimes as small as pins’
heads, at others as large as a silver penny; having the pestilential
poison chiefly collected at their bases,” &c.
That the plague was by the ancients reckoned a disease of a nature
different from all others, appears from Galen, as quoted by Deusingius.
“What is called the _pestilence_ is most properly remarked by Galen
not to be a _genus_ of any known disease. For whatever diseases and
symptoms are associated with the plague, truly and properly so called,
the same are wont to be called _pestilential_ diseases; of which indeed
there are an innumerable multitude, and these not always nor every
where the same.”[61]
[61] Non esse certi morbi genus, id quod _pestilens_ vocatur,
rectissime notatum a Galeno est (3 Epid. comm. 3. t. 20.) quicunque
enim morbi ac symptomata consociantur pesti veræ proprieque diclæ,
ijdem _morbi pestilentes_ apellari consuevere, quorum equidem
innumerabilis existit cohors, ac non semper et ubivis eadem.
(_Deusing. de Peste_, _Sect._ iii.)
In like manner Diemerbroeck, as quoted by Allen, gives his opinion,
that “The plague is something different from a fever, and a fever is
only a symptom of it, as I have _very often_ observed; and therefore
some very ill define the plague by a fever, since a fever does not
essentially belong to it.... A pestilential fever, the _companion
of the plague_, is not occasioned by a pestilential venom, but by
the mediation of putrefaction; that is, it is not produced because
the humours are infected with the pestilent venom, but because the
heart, being irritated, overwhelmed and much weakened by the pestilent
venom, can neither duly digest and rarefy, nor govern and sufficiently
discharge the infected humours; which for this reason putrefy and
acquire a preternatural heat, and so excite a fever; which by reason
of the foresaid secondary cause, is different and distinct from the
plague, and a symptom of it. This is confirmed both by the maxims and
authority of the ancients and moderns, as well as by practice, and
evident examples.”
Thus it appears, both by fair reasoning by induction from facts, and
from the authority of the greatest physicians, that the plague is
certainly a disease by itself, and entirely distinct from all others.
Hence it follows, that, though we could investigate the causes of
fever in their utmost extent, we might still be ignorant of the true
plague. That nothing, however, may be omitted, let us now consider what
physicians have advanced on this subject, and what progress they have
made in ascertaining the sources from whence so many direful calamities
are derived.
In an inquiry of this kind, or indeed concerning any cause whatever,
it is plain that the nature of the effect must be first understood.
Fever then being an _effect_, we must begin with investigating its
_nature_. But fever itself is only manifest by certain changes in the
human body. Before we can investigate the nature of fever, therefore,
we must investigate the human body, and that in a manner very different
from what we did before. We must now consider the sources of life; in
what manner the vital principle acts upon the body, and by what means
its motions can be disturbed, or how they may be rectified when once
disordered, &c. &c.
The systems of medicine before the time of Boerhaave are now so
generally exploded, that it is needless to take any notice of them;
and the reputation of Boerhaave himself in this way seems to be almost
expiring. His doctrines, nevertheless, merit some attention, because
he takes into account a principle overlooked by succeeding theorists,
viz. the _cohesion_ of the parts of the body. That he did so is
evident, from his having written upon the diseases of a _weak and
lax_ fibre, and the diseases of a _strong and rigid_ fibre. In other
respects he followed in a great measure the mechanical physicians of
the former century. He therefore took but little notice of the nervous
system, as being less subject, or indeed to appearance not at all
subject, to the known laws of mechanics. The blood was more manageable.
The microscopical discoveries of Lewenhoeck furnished an excellent
foundation for his system. This celebrated observer had discovered, or
fancied he had discovered, that the red part of the blood is composed
of globules. Inaccurate indeed these globules must have been, since
each of them was composed of six; four touching one another in the
middle, with one above, and one below, thus [Inline illustration].
The serum was said to be composed of single globules, and by this
attenuation it was supposed that the fluid, instead of red, appeared
of a _yellow_ colour. Still, however, this was insufficient. Each of
the yellow globules was _discovered_ (either by fancied observations
or by conjecture, it matters not which) to be composed of six others,
which, singly taken, might constitute the lymph or some other fluid;
and thus, like the number of the Beast, we might go on by sixes to the
end of the chapter, and solve all the phenomena of nature. In justice
to the microscopists, however, it must be observed, that some of
them have given a much less fanciful account of the structure of the
blood than Lewenhoeck. Mr. Hewson found it composed of vesicles, or
small bladder-like substances, with a black spot in the middle. These
vesicles dissolved in pure water, but kept their original form, which
he says was as flat as a shilling, when a small portion of neutral salt
was added to the fluid. The solid particles he supposed to be produced
by the lymphatic system; the black particles by the spleen.
The supposed observations of Lewenhoeck were of considerable use to
Boerhaave in the forming of his system of medicine, though they seem
not to have accorded very well with his doctrine of lentor or viscidity
in the blood. But, let this be as it will, having laid it down as the
foundation of his theory, that the diseases of the body proceeded from
too great a laxity of the fibres, or from too great a rigidity of them,
and a great many from this _lentor_, his practice was accordingly
directed to such medicines as he imagined would remove these supposed
causes of disease. As the lentor of the blood was one of his favourite
suppositions, he was therefore perpetually at war with this imaginary
enemy, and dealt very much in saponaceous medicines with a view to
break it down. But here it is evident that this great man was mistaken,
even though we should allow the existence of lentor as much as he
pleased. The viscidity, _lentor_, or any other state of the blood, is
an _effect_ of something. It is part of that state into which the body
is brought by the disease. The efforts of the physician therefore ought
to be against that which produces the lentor; for, unless this be done,
the cause of the disease must perpetually counteract the medicines by
producing new lentor as fast as they destroy it; and besides, must have
greatly the advantage of the physician, by being already in possession
of the whole mass of blood, while the medicines can only enter it very
gradually, and that by the stomach and lacteals, instead of being
instantly mixed with it, and exerting their power immediately upon the
fluid itself.
But besides this mistake, which is common to other systems, Boerhaave’s
lentor has been denied, and that upon such strong grounds that it is
now universally exploded. Another system quickly succeeded, in which
every thing was managed by the nerves. This was introduced by Hoffman,
adopted, and perhaps improved, by Dr. Cullen, under whose auspices
it acquired such a degree of celebrity, that for a long time it was
dangerous to write or speak against it; and the person who had the
audacity to do so underwent a kind of medical proscription from the
Edinburgh College and all its students. According to this celebrated
theorist, the brain is that part of the body first formed in the
embryo; it may be seen with nerves proceeding; from it long before the
heart or any blood-vessel belonging to it is visible. Hence we are to
conclude that this part is necessary to the existence of every other
part of the body, though it doth not appear that they are essentially
necessary to its existence. The superiority of the nerves to all other
parts being thus established, the Doctor undertook to prove that
all other parts of the body were formed from them; that the body is
nourished immediately from them, and in short that the whole body is
in such subjection to the nervous system, that, except for the mere
purpose of distending the vessels, we can scarcely know for what end
the blood exists; since the nerves can alter its consistence, or that
of any of the fluids secreted from it, by a mere affection of that
system, without any thing either added to or taken from the vital fluid.
Thus we were compelled to believe that all diseases at their first
origin are affections of the nervous system, from whence they are
propagated through the whole body. The Cullenian practice in acute
diseases, of which the plague is the most violent, was built upon a
maxim of Hoffman: “Atonia gigoit spasmos:” _Atony produces spasms_. In
explaining the nature of typhus fever, therefore, with which he classes
the plague, the Doctor supposed that the contagion acted first upon
the nervous system, by producing therein a debility. The immediate
effect of this debility is a _spasm_, or preternatural contraction of
the capillary vessels, or extremely small arteries. Hence the blood
finds some difficulty in circulating, and the patient is seized with
shivering, and has a sense of cold. When this has continued for some
time the system begins to _re-act_ against its enemy; the spasm is
resolved, and, the reaction of the system continuing, the action of the
heart and arteries is augmented, and the body becomes warmer.
Thus the coldness, shivering, and consequent heat, which constitute
the first attack of fever, are very plausibly explained; but in the
mode of cure this learned physician fell into the same mistake with Dr.
Boerhaave; for though spasm is undoubtedly, even according to himself,
an _effect_, he directs his medicines entirely against it, as if it
were a _cause_. Thus, forgetting what he had just before advanced,
that the spasm is occasioned by debility, he recommended the most
debilitating medicines and regimen to cure people already too much
debilitated; and to such practice his enemies alledged that many fell
victims. The theory and practice, however, still kept its ground; and
as great numbers of students were every year bred up in the belief of
it at Edinburgh College, who carried the principles of their teacher to
all parts of the world, it bade fair for becoming universal. But, in
the midst of this eclat, the whole system received such a rude shock
from the doctrines of _John Brown_, though at that time not even M. D.
as it hath not yet recovered.
Though the author of the new system contended, as much as Dr. Cullen,
for the supremacy of the nerves, he did not upon that foundation
attempt to establish his practice. He considered the living body as one
machine, the _whole_ of which might be acted upon, and always was acted
upon by certain powers. It possesses a certain inexplicable property
called _excitability_, capable of being augmented or diminished. Every
power which augments the _excitability_ he called a _stimulus_; the
opposite would have been a _sedative_; but according to this system
there is not any sedative, nor can there be one in nature. The reason
is, that excitability itself has no existence but in consequence of
the action of certain powers called _stimulants_. The total subduction
of these reduces the excitability to nothing; of consequence no power
can act against it in a state of non-existence. What other physicians
call _sedatives_, therefore, according to the new system, are only weak
_stimulants_. The fallacy of such reasoning is obvious; but as it does
not affect the practice, we shall not spend any time in considering it
further.
On the principles just now laid down, the Brunonian system divides all
diseases to which the human body is liable into two great classes;
the one produced by too much excitement, the other by too little. The
former contains those diseases by other physicians called inflammatory;
the latter such as are called nervous, putrid, or all in which the
powers of life are too weak, and require to be supported. This last
is supposed to be much more numerous than the former; and in the cure
of these it was that the founder of the system appeared to greatest
advantage. A most violent altercation took place between Dr. Brown and
the Edinburgh College; yet, notwithstanding all the influence of the
professors, and their unanimous opposition to the new doctrines, they
found themselves ultimately unable to resist a single man unsupported
either by wealth or reputation. The plausibility of his system, and
its being obvious to every capacity, overcame every obstacle; so that
even the practice of the Cullenians themselves underwent considerable
alterations. It is not, however, to be denied that the system hath
been considerably improved, or at least altered, by some of Dr.
Brown’s pupils, who have had the advantage of extensive practice,
and of visiting many different countries; which the Doctor himself
never had. His materia medica was besides exceedingly confined; the
only medicines he had any great opinion of, being laudanum and ardent
spirits. The Peruvian bark he held in very little estimation, as being
a weak stimulus. He seems to have been unacquainted with the virtues
of mercury, except in the venereal disease, and most probably would
have given laudanum in those cases of fever where mercury is found by
others to be so efficacious. But this deficiency hath been abundantly
supplied by some of his followers. In a work entitled “The Science
of Life,” published by Dr. Yates and Mr. McLean, practitioners in
the East Indies, we find mercury exhibited in prodigious doses. As a
specimen we shall select their third case, which was a dysentery. On
the first of September the patient took two grains of calomel and as
much opium every two hours. This was continued for two days. On the
third, the dose was given every hour; besides which, he had half an
ounce of mercurial ointment with a drachm of calomel rubbed into his
body. Next day the pills were continued, and the quantity of ointment
tripled by thrice rubbing in. This was continued for three days, at
which time, an eruption on the skin appearing, it was feared he could
not be salivated; this eruption being a sign that no salivation could
be produced. The same mode of treatment, however, was persisted in.
September 7th the calomel in the pills was augmented to four grains;
the warm bath was used, and the ointment continued; but at night twenty
grains of calomel and six of opium were given every two hours. At the
same time two ounces of ointment, with four of calomel, were ordered
to be rubbed in. Next day, though his pulse was almost imperceptible,
and his extremities cold, “the medicines were continued as far as
circumstances would admit;” with what view it is not said, nor indeed
is it easy to be discovered. At one in the morning, however, the
patient died; an event not at all surprising. Our authors excuse
themselves for this failure by saying that the viscera of the patient
were diseased, as was evinced by the impossibility of exciting a
salivation; and “that when a patient is evidently incurable by the
common practice, it becomes the duty of the practitioner to depart from
it.”
No doubt we may readily assent to both these assertions; but though
a patient be evidently incurable by the common practice, or by any
other, there is no necessity for killing him, or for persevering in
a course of violent medicines that evidently make him worse. The
whole of this case indeed strongly militates against the doctrine of
excitement; for if mercury be such a powerful stimulus to the powers
of life in general, how comes it to pass that in the present case the
unhappy patient, instead of being in the smallest degree excited, was
prodigiously debilitated, and that from the very first time of taking
the medicines. This will appear from the following table, exhibiting
the symptoms of the disease as they kept pace with the medicines taken.
DAYS OF THE MEDICINES TAKEN. SYMPTOMS.
MONTH.
_August 29 Ordinary doses of Pain of bowels,
& preceding._ mercury and opium. and frequent stools,
growing worse.
_Sept. 1 & 2._ Opium and mercury, Still increasing.
two grains
each, every two
hours; besides opiate
draughts.
3d The opium and Stools very frequent,
mercury as before, with violent
but now given every pain in the bowels;
hour; half an extreme thirst,
ounce of mercurial tongue furred, and
ointment, with 60 no sleep.
grains calomel.
4th Pills as usual. Vomiting during
Ointmt. thrice rubbed the night. Tongue
in, once with brown and furred.
120 grains of mercury.
5th Medicines as before. Violent pain in bowels.
6th Medicines as before. Extreme pain on
pressing the arch
of the colon; frequent
stools, profuse
sweats, great dejection
of spirits.
7th Pills as before, As yesterday. An
with four grains of eruption on the skin.
calomel. Mercury At night incessant
in the ointment increased stools, with violent
to half an pain in the belly;
ounce. Warm bath. profuse sweat.
At night an ounce
of mercurial ointment,
with two ounces
calomel.
8th Pills, ointment & Incessant stools
calomel as before. with violent pain;
Warm bath thrice. at night with blood.
At night two ounces Extreme debility.
ointment, with four
of calomel.
9th Medicines of the Stools innumerable;
same kind, as many extremities
as could be taken. cold, pulse scarce to
be felt.
10th Death at one in
the morning.
From a consideration of this patient’s symptoms, in comparison with the
quantity of mercury taken, it most evidently appears, that it acted
in no other way than as an irritating poison; affecting, with extreme
violence, the already diseased intestines, and, instead of exciting
the vital powers of the whole system, manifestly destroying them. Let
it not be imagined, however, that this case is selected from the rest
merely because it was fatal, or because it affords an opportunity of
finding fault with the practice recommended in the book. It is the only
one in which the mercury had a fair trial; and even here it was not
very fair, as being conjoined with a great quantity of opium. In the
other cases, which terminated favourably, the mercury was overpowered
by such horrible doses of opium, that we cannot tell which medicine
had the greatest share in the cure; besides, that in other cases the
patients were allowed the free use of wine, which we all know to be a
powerful stimulant and cordial; but it is not said that the poor man,
whose case is above related, had a single drop of wine, or any thing
else, except opium, to support him against the action of such a violent
medicine.
On this case it is of importance still to remark, that it affords,
in the strongest manner, an argument against what our authors say,
p. 86, that “mercury acts by supporting the excitement of the whole
body, it invigorates each particular part; and thus occasions, to a
certain extent, the regeneration of those organs which may have been
injured by disease.” In the instance adduced, there is no evidence of a
stimulus upon any other part of the system than the bowels, which were
already debilitated or diseased in such a manner that they could not
bear it. The system in general, instead of being excited, was sunk and
debilitated from the very first moment, until at last the excitement
terminated entirely by the patient’s death. But further: There is very
little probability that mercury or any other medicine whatever can
prove a general stimulus, and that for the following reasons.
1. No medicine can assimilate with the substance of the body. Medicines
properly so called are here alluded to. Food or drink of any kind taken
for the support of the body while in health, however they may act
medicinally upon occasions, are excepted.
2. The body is composed of many various substances, each differing in
its nature from the other. The nature of the medicine, whatever it may
be, is uniform, and cannot act upon substances of different kinds in
an uniform manner; and without this there can neither be an universal
stimulant, nor an universal debilitant.
3. All medicines, being incapable of assimilation with the body,
must be considered, when taken into it, as foreign matter; and the
introduction of them at any rate is in fact the creating of a disease.
This is evident from multitudes of instances where people by quacking
with themselves, and taking medicines unnecessarily, have destroyed
their health.
4. As every medicine has one peculiar nature, and one mode of action
in consequence of that nature, it must, when introduced into the body,
where there are fluids of various natures, act upon one of them more
than the rest; and this may be called the _chemical_ action of that
medicine upon the body.