<h2>PART I.</h2>
<h2>OF THE NATURE OF <i>CONTAGION</i>.</h2>
<p>That the Reasonableness
of any Method, which
shall be proposed to prevent
the spreading of <i>Contagious</i>
Diseases, may the better appear,
it is necessary to premise somewhat
in general concerning <i>Contagion</i>,
and the Manner, by which it acts.</p>
<p>Contagion is propagated by
three Causes, the <i>Air</i>; <i>Diseased
Persons</i>; and <i>Goods transported from
infected Places</i>.</p>
<p>We shall therefore first enquire
what alteration of the <i>Air</i> it is,
that makes it <i>infectious</i>; and then,
by what Means it communicates its
noxious Quality to other Bodies.</p>
<p>The ancientest and best Authors
of Physick, who lived in a Country
more exposed to these Calamities
than ours, observed the Constitution
of the <i>Air</i>, which preceded
<i>Pestilential Fevers</i>, to be great <i>Heats</i>
attended with much <i>Rain</i> and <i>Southerly
Winds</i><SPAN name='r1' /><SPAN href='#f1' class='c007'><sup>[1]</sup></SPAN>: And one of Them
takes particular Notice, that no other
than a <i>moist</i> and <i>hot</i> Temperament
of the <i>Air</i> brings the <i>Plague</i>;
and that the Duration of this Constitution
is the Measure of the Violence
of the Distemper<SPAN name='r2' /><SPAN href='#f2' class='c007'><sup>[2]</sup></SPAN>.</p>
<p>The Natural History of several
Countries confirms this Observation;
in <i>Africa</i> particularly, if Showers
fall during the sultry Heats of
<i>July</i> and <i>August</i>, the <i>Plague</i> ensues
thereupon, with which whosoever
is infected hardly escapes<SPAN name='r3' /><SPAN href='#f3' class='c007'><sup>[3]</sup></SPAN>.</p>
<p>It has besides been remarked in
all Times, that the Stinks of <i>stagnating
Waters</i> in hot Weather, <i>putrid
Exhalations</i> from the Earth;
and above all, the Corruption of
dead <i>Carcasses</i> lying unburied, have
occasioned <i>infectious Diseases</i>.</p>
<p>From hence it appears to be a
<i>Concurrence</i> of Causes, that produces
Diseases of this Kind; which
must not only meet, but exert their
Force together for a considerable
time. And when this happens,
their first effect is a Degree of <i>Stagnation</i>
in the Air, which is afterwards
followed by <i>Corruption</i> and
<i>Putrefaction</i>.</p>
<p>And upon this account it is, that
those Countries are chiefly liable to
these Calamities, where not only
the <i>Heats</i> are very great, and the
<i>Weather</i> continues long in the same
State; but the <i>Winds</i> (the Use of
which is by Motion to purify the
Air) do not shift and change so often
as they do in Northern Climates.</p>
<p>Indeed <i>Plagues</i> seem to be of the
Growth of the <i>Eastern</i> and <i>Southern</i>
Parts of the World, and to be transmitted
from them into colder Climates
by the Way of <i>Commerce</i>.
Nor do I think, that in this <i>Island</i>
particularly there is any one Instance
of a <i>Pestilential</i> Disease among
us of great Consequence;
which we did not receive from other
<i>infected</i> Places.</p>
<p>This I the rather mention, because
it is a common Opinion, and
propagated by Authors of great
Name, that we are usually <i>visited</i>
with the <i>Plague</i> once in 30 or 40
Years; which is a mere Fancy without
any Foundation either in Reason
or Experience: and therefore
People ought to be delivered from
the Subjection to such vain Fears.</p>
<p>On the contrary, though we
have had several Strokes of this
kind, yet there are Instances of
bad <i>Contagions</i> from abroad being
brought over to us, which have
proved less malignant here by our
Air not being disposed to receive
such Impressions.</p>
<p>The <i>Sweating Sickness</i>, called the
<i>Sudor Anglicus</i> and <i>Febris Ephemera
Britannica</i>, because it was commonly
thought to have taken its Rise
here, was most probably of a foreign
Original, and no other than a
<i>Plague</i> abated in its Violence by the
mild Temperament of our Climate.</p>
<p>For, we learn from Histories, that
the first time this was felt here,
which was in the Year 1485, it began
in the Army, with which King
<i>Henry</i> VII. came from <i>France</i>,
and landed in <i>Wales</i><SPAN name='r4' /><SPAN href='#f4' class='c007'><sup>[4]</sup></SPAN>; and it was
then thought to have been brought
into <i>France</i> from the famous Siege
of <i>Rhodes</i> by the <i>Turks</i> 3 or 4 Years
before. And of the four Returns,
which this has made since that
Time; two, viz. <i>those</i> in the Years
1527, and 1528, may very justly
be suspected to have been owing to
the <i>Pestilence</i>, which at those Times
raged in <i>Italy</i>, particularly at <i>Florence</i>
and <i>Naples</i><SPAN name='r5' /><SPAN href='#f5' class='c007'><sup>[5]</sup></SPAN>. And the others
were very probably from a <i>Turkish</i>
Infection.</p>
<p>I call this Distemper a <i>Plague</i>
with lessened Force, because the
Symptoms of it were of that kind,
though in a less Degree; as great
<i>Faintness</i> and <i>Inquietudes</i>, inward
<i>Burning</i>, <i>Pain</i> in the <i>Head</i>, a <i>Delirium</i>
&c. All which were accompanied
with profuse <i>Sweats</i>, and the
Disease lasted but 24 hours. And
though for want of Care and due
Management many died of it; yet,
as a learned and wise <i>Historian</i><SPAN name='r6' /><SPAN href='#f6' class='c007'><sup>[6]</sup></SPAN>
observes, <i>It appeared rather to be a
surprize of Nature than obstinate to
Remedies, for if the Patient was
kept warm with temperate Cordials,
he commonly recovered</i>.</p>
<p>And I cannot but take Notice,
as a Confirmation of what I have
been advancing, that we had here
the same kind of Fever in the Year
1713, about the Month of <i>September</i>,
which was called the <i>Dunkirk
Fever</i>, as being brought by
our Soldiers from that Place; where
it was indeed a Malignant Disease
attended with a <i>Diarrhœa</i>, <i>Vomiting</i>,
&c. and probably had its Original
from the Pestilential Distemper,
which some time before broke
out at <i>Dantzick</i> and <i>Hamburgh</i>:
But with us was much more mild,
beginning only with a Pain in the
Head, and by very easy Means
went off in large <i>Sweats</i>, after a
Day's Confinement.</p>
<p>There being in every Air a
greater Disposition to <i>Contagion</i> at
one Time than another, we have
indeed sometimes felt this Calamity
with greater Fury; as particularly
the last time in the Year 1665;
when it continued in this <i>City</i> about
ten Months, and swept away
by computation 97306 Persons:
But it was generally allowed, that
the <i>Contagion</i> came by <i>Cotton</i> imported
from <i>Turkey</i><SPAN name='r7' /><SPAN href='#f7' class='c007'><sup>[7]</sup></SPAN>; and the long
Duration of it, I believe, may justly
be charged up the unhappy Management
of infected Houses, which
was then directed by Publick Authority;
as I shall shew anon.</p>
<p>And the History of the most terrible
of all the Plagues, that ever were
in these Parts of the World, which
was that in the Year 1349, gives
a manifest Proof from whence all
<i>Europe</i> may trace the Origine of
these Evils, viz. from <i>Asia</i>: for
<SPAN name='r8' /><SPAN href='#f8' class='c007'><sup>[8]</sup></SPAN>This taking its Rise in <i>China</i> in
the Year 1346, advanced through
the East <i>Indies</i> to <i>Syria</i>, <i>Turkey</i>,
<i>Ægypt</i>, <i>Greece</i>, <i>Africa</i>, &c. In 1347
some Ships from the <i>Levant</i> carried
it to <i>Sicily</i>, <i>Pisa</i>, <i>Genoa</i>, &c. In
1348 it got into <i>Savoy</i>, <i>Provence</i>,
<i>Dauphiny</i>, <i>Catalonia</i>, <i>Castile</i>, &c.
In 1349 it seized <i>England</i>, <i>Scotland</i>,
<i>Ireland</i>, and <i>Flanders</i>; and
in the next place <i>Germany</i>, <i>Hungary</i>,
and <i>Denmark</i>; and in all
these Countries made most incredible Havock.</p>
<p>But to return to the Consideration
of the Air, which we left in a
putrid State: It is to be observed,
that Putrefaction is a kind of Fermentation,
and that all Bodies in
a Ferment emit a volatile active Spirit,
of Power to agitate, and put
into intestine Motions, that is, to
change the Nature of other Fluids
into which it insinuates it self.</p>
<p>It were easy to shew from the
best <i>Theory</i> of Fevers<SPAN name='r9' /><SPAN href='#f9' class='c007'><sup>[9]</sup></SPAN>, how the
Alterations made in the <i>Blood</i> this
Way will favour <i>Pestilential</i> Diseases,
by rendring the Body obnoxious to
them: But the Digression would
be too great.</p>
<p>THIS is one step towards <i>Contagion</i>.
The next, as it seems to me,
proceeds after this Manner. The
Blood in all <i>Malignant Fevers</i>, especially
<i>Pestilential</i> ones, at the latter
End of the Disease, does like
Fermenting Liquors throw off a
great Quantity of active Particles
upon the several <i>Glands</i> of the Body,
particularly upon those of the
Mouth and Skin, from which the
Secretions are naturally the most
constant and large. These, in <i>Pestilential</i>
Cases, although the Air
be in a right State, will generally
infect those, who are very near to
the sick Person; otherwise are soon
dispersed and lost: But when in an
evil Disposition of <i>This</i> they meet
with the subtle Parts, its Corruption
has generated, by uniting
with them they become much more
active and powerful, and likewise
more durable and lasting, so as to
form an <i>Infectious Matter</i> capable
of conveying the Mischief to a great
Distance from the diseased Body,
out of which it was produced.</p>
<p>They who know what strange
Attractions and Combinations are
made by volatile Spirits will understand
this Reasoning; especially if
they consider, how easily all kinds
of <i>Effluvia</i> are diffused in a warm
Air, such as we have described an
Infectious one to be; and further,
of how penetrating a Force the finest
Parts of Animal Juices are; of
which the strange Stench of a mortified
Limb, upon a Body yet living,
will convince any one.</p>
<p>A corrupted State of Air is without
doubt necessary to give these
<i>Contagious Atoms</i> their full Force;
for otherwise it were not easy to
conceive how the <i>Plague</i>, when
once it had seized any Place, should
ever cease, but with the Destruction
of all the Inhabitants: Which
is readily accounted for by supposing
an Emendation of the Qualities
of the Air, and the restoring
of it to a healthy State capable of
dissipating and suppressing the Malignity.</p>
<p>On the other hand it is evident,
that <i>Infection</i> is not received from
the Air it self, however predisposed,
without the Concurrence of something
emitted from <i>Infected</i> Persons;
because, by strictly preventing
all Intercourse of Infected Places
with the Neighbourhood, it may
be effectually kept from spreading:
Whereas the least Wind must necessarily
convey whatever noxious
Quality resides in the Air alone,
even to a great Distance. Of this
we have had a fresh Proof in the
present unhappy <i>Plague</i> in <i>France</i>,
which, by keeping careful Guard,
was confined for a considerable
Time within the Walls of <i>Marseilles</i>;
so that none of the adjacent
Villages suffered any thing by
it; till at length some Persons
finding Means to escape carried the
Infection along with them. And
we find, they have been able, by
the like Care, still to restrain it
within moderate Bounds.</p>
<p>This is the Manner by which
Infectious <i>Effluvia</i> are generated;
The Way, by which a sound Person
receives the Injury, I suppose most
commonly to be this. These <i>Contagious</i>
Particles being drawn in with
the Air we breath, they taint in
their Passage the <i>Salival</i> Juices,
which being swallowed down into
the Stomach presently fix their Malignity
there; as appears from the
<i>Nausea</i> and <i>Vomiting</i>, with which
the Distemper often begins its first
Attacks. Though I make no Question
but the <i>Blood</i> is also more immediately
affected by hurtful Particles
being mixed through Inspiration
with it in the Lungs.</p>
<p>The third Way, by which we
mentioned <i>Contagion</i> to be spread, is
by <i>Goods transported from infected
Places</i>. It has been thought so difficult
to explain the Manner of
<i>this</i>, that some Authors have imagined
<i>Infection</i> to be performed by
the Means of <i>Insects</i>, the <i>Eggs</i> of
which may be conveyed from Place
to Place, and make the Disease
when they come to be <i>hatched</i>. As
this is a supposition grounded upon
no manner of Observation, so I
think there is no need to have Recourse
to it. If, as we have conjectured,
the <i>Matter of Contagion</i>
be an active Substance, perhaps in
the Nature of a <i>Salt</i>, generated
chiefly from the Corruption of a
<i>Humane Body</i>, it is not hard to
conceive how this may be lodged
and preserved in soft, porous Bodies,
which are kept pressed close
together.</p>
<p>We all know how long a time
<i>Perfumes</i> hold their <i>Scent</i>, if wrapt
up in proper Coverings: And it is
very remarkable, that the strongest
of these, like the <i>Matter</i> we are
treating of, are mostly <i>Animal</i>
Juices, as <i>Mosch</i>, <i>Civet</i>, &c. and
that the Substances found most fit
to keep them in, are the very same
with those which are most apt to
receive and communicate <i>Infection</i>,
as, <i>Furrs</i>, <i>Feathers</i>, <i>Silk</i>, <i>Hair</i>,
<i>Wool</i>, <i>Cotton</i>, <i>Flax</i>, &c. the greatest
Part of which are likewise of
the Animal Kind; which Remark
alone may serve to lead Us a little
into the true Nature of <i>Contagion</i>.</p>
<p>From all that has been said, it
appears, I think, very plainly, that
the <i>Plague</i> is a real Poison, which
being bred in the Eastern or Southern
Parts of the World, maintains
it self there by circulating from <i>Infected</i>
Persons to Goods; which is
chiefly owing to the Negligence of
the People in those Countries, who
are stupidly Careless in this Affair:
That when the Constitution of the
Air happens to favour Infection, it
rages there with great Violence;
That at that Time more especially
diseased Persons give it to one another,
and <i>Contagious Matter</i> is lodged
in Goods of a loose and soft
Texture, which being packt up,
and carried into other Countries,
let out, when opened, the imprisoned
Seeds of Contagion: And
lastly, That the Air cannot diffuse
and spread these to any great Distance,
if Intercourse and Commerce
with the Place infected be strictly
prevented.</p>
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