ds there into the like
Agitation and Disorder.

THE Body, I suppose, receives them these two ways, by the _Breath_, and
by the _Skin_; but chiefly by the former.

I THINK it certain that _Respiration_ does always communicate to the
Blood some Parts from the Air: Which is proved from this Observation,
that the same Quantity of Air will not suffice long for breathing,
though it be deprived of none of those Qualities, by which it is fitted
to inflate the Lungs and agitate the Blood, the Uses commonly ascribed
to it. And this is farther confirm'd by what the learned Dr. _Halley_
has inform'd me, that when he was several Fathom under Water in his
_Diving Engine_, and breathing an Air much more condensed than the
natural, he observed himself to breath more slowly than usual: Which
makes it more than probable, that this conveying to the Blood some
subtile Parts from the Air, is the chief Use of _Respiration_; since
when a greater Quantity of _Air_ than usual was taken in at a time, and
consequently more of these subtile Parts received at once by the Blood,
a less frequent _Respiration_ sufficed.

AS to the _Skin_, since there is a continual Discharge made thro' its
innumerable _Pores_, of the matter of _insensible Perspiration_ and
_Sweat_; it is very possible that the same Passages may admit subtile
Corpuscles, which may penetrate into the inward Parts. Nay it is very
plain that they do so, from what we observe upon the outward Application
of _Ointments_ and warm _Bathings_: which have their Effects by their
finest and most active Parts insinuating themselves into the Blood.

IT is commonly thought, that the _Blood_ only is affected in these Cases
by the morbific _Effluvia_. But I am of opinion, that there is another
Fluid in the Body, which is, especially in the beginning, equally, if
not more, concerned in this Affair: I mean the _Liquid of the Nerves_,
usually called the _Animal Spirits_. As _this_ is the immediate
Instrument of all Motion and Sensation, and has a great Agency in all
the glandular Secretions, and in the Circulation of the Blood itself;
any considerable Alteration made in it must be attended with dangerous
Consequences. It is not possible that the whole Mass of Blood should be
corrupted in so short a Time as that, in which the fatal Symptoms, in
some Cases, discover themselves. Those Patients of the _first Class_,
mentioned in the beginning of this Discourse, particularly the _Porters_
who opened the in