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PAGE
(Vide Sect. XLVII. page 561); may
we not thence infer, that they de-
pend both for their Power of Ac-
tion on the fame Caufe?
2. Thofe Parts which are most supplied with Blood Veffels are moft fenfible. 3. Parts when inflamed are rendered acutely fenfible.
An Experiment made by Dr. BEDDOES, where VITAL AIR increased the Pain of a Blifter, and relief was immediately ob- tained by fixed, and azotic, Airs.
Patients, who have inhaled the VITAL AIR, feel a great Hilarity of Spirits.
Whether the enlivening Influence of Wine
may not depend upon the Blood, from an
increased Attraction, abforbing more VITAL
AIR.
SECT. XXXV.
LAW II. A TOO GREAT
EXCITEMENT OF ANY ORGAN
EXHAUSTS THE EXCITABILITY
OF THE CONTRACTILE FIBRE.
Every STIMULUS which acts upon one of the
Fibres, affects the others at the fame
Time,
-
Hence the SYMPATHY of feparate Parts,
formerly explained by the Medium of
Nerves,
361
ib.
Hence
Hence the irritable Fibres form a SYSTEM, in
which the integral Parts act continually
upon the Whole, while the Whole re-acts
upon the Parts, so that every Stimulus
which acts upon any Set of Fibres in this
Syftem, will deprive that Part of its Irrita-
bility; but this Lofs will be foon repaired
by the SYSTEM, and every Fibre will fur-
nish, in proportion to its Proximity, some
Share of its own Irritability to fupply the
Lofs,
Thus a powerful Stimulus applied to any one
Part extends its Influence over the whole
Syftem,
The IRRITABLE PRINCIPLE is therefore never
in a permanent Condition, but rather bears
refemblence to the Leyden Phial, which is
alternately charging, discharging, and dif-
charged,
When the Sum of the STIMULI acting upon
362
862
the Fibre is too great, the Fibre loses more
IRRITABILITY than it receives, and of
course finds itself in the State of EXHAUS-
TION, which is either, 1. Temporary, or
2. Irreparable, 363
1. Of Temporary Exhauftion.
In the State of TEMPORARY EXHAUSTION the
Fibre will not contract upon the Applica-
tion of Stimuli from want of the irritable
Principle,
{
On this Principle the monthly Periods in wo- men depend, -
Thus alfo, during the Operation of an Eme- tic or Cathartic, the Stomach and Bowels are alternately in a State of Excitement and Repofe,-
And thus the most violent Pains of a parturient
Woman, if not effectual for the Expulfion
of the Offspring, ceafe for a Time, and are
then renewed, -
{The Exacerbations of Fevers alfo depend upon
THIS PRINCIPLE,
{Of the Motions of the SENSITIVE PLANT,
{An Experiment with one of these Plants,
364
By the fhaking of a Carriage, all its Leaves
were clofed, which continued for four and
twenty Hours,
It having then opened its Leaves, a State of
TORPOR enfued, and these did not close for
three Days and as many Nights,
b
At
VOL. III.
At other Times it fhut up and opened its
Leaves regularly each Night and Morning, 365
All the periodical Motions of Animals, as well
as Plants, may be explained upon THIS
PRINCIPLE,
{So may all periodical Difcafes,
{Other Examples,
366
The HEAT of the Sun, or ELECTRICITY, ex-
haufts for a Time the Irritability of the Hedyfarum Gyrans and Mimofa,
{Of the Effects of WINE,
{4
A certain Quantity of WINE calls forth all the
Vigour and Genius of a Man, -
{Beyond this, and he finks into the mere
Brute, and finally falls asleep,
A Conjecture that JOHN BROWN took the first Hint of his
Philofophy from ARMSTRONG's Poem on the Art of
Preferving Health,
367
A Paffage from that Poet, where not only the Thought, but
in many Places THE WORDS, are the fame as those of
Brown,
This is not meant to derogate ought from the Merit of JOHN
BROWN,
gence
Others might at a chance Time shine forth like a Meteor,
but in the Writings of JOHN BROWN we fee the Efful.
of the Noon-day,
Of the Effects of OPIUM, -
- 368
1. It occafions an increased Action in the
System, -
2. In confequence of this Expence of the IRRITABLE PRINCIPLE, a State of Torpor enfues, -
3. During this Torpor the IRRITABLE PRINCIPLE becomes accumulated, and the natural Stimuli produces in confe- quence a fecond Over-exertion,
And thus an unequal Balance of the Ex-
CITABILITY, and of the NATURAL STI-
MULI continues for two or three Days, ib.
If a fecond Dofe of OPIUM be exhibited before
the Fibres have regained their natural
Quantity of due Excitability, its Effects
will be much less than the former, because
the EXCITABILITY is in part exhausted by
the previous Excess of Exertion, 369
But when a Stimulus is repeated at fuch dif
tant Intervals of Time, that the natural
Quantity of EXCITABILITY becomes com-
pletely restored in the acting Fibres, it will
then act with the fame Energy as when firft
applied,
Hence the Danger of an Overdose, when we
intermit a Remedy which we were before
in the HABIT of employing,
{An EXAMPLE of this fhewn in a Note,
b 2
370
2. Of