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{
I. If the SUPPLY of the IRRITABLE PRIN-
CIPLE to the moving Fibre be equal to the
Expenditure by the Action of Stimuli, the
Fibre is then faid to be in a State of
TONE,
-
II. If the EXPENDITURE exceeds the Supply of
THIS PRINCIPLE to the Fibre, it is faid to
be in a State of EXHAUSTION,
III. But if the SUPPLY given to the moving
Fibre exceed the Expenditure, the Fibre is
then faid to be in a State of ACCUMU- LATION,
SECT. XXXVIII. OF COLD.
PAGE
409
ib.
-During the Winter, by the Absence of the
Stimulus of Heat, and in part of Light,
Plants and many Animals become TORPID, 410
In confequence of this diminished Action, their
IRRITABILITY ACCUMULATES, which ma-
nifefts itself at the return of Spring, -
A flight Degree of Heat then produces the
moft powerful Effects upon the Fibre thus
delicately Irritable, -
{ Dr. HALE's Experiments respecting the Rifing
of the Sap in the VINE, -
d 2
411
The
The Conclufions to be drawn from his Expe- riments are,
I. That the Sap flows in the Vine
during the SPRING, quicker than the
Blood in the Veffels of a Horse; that
its Progress is confiderably flower in
the SUMMER than in SPRING; very
languid in AUTUMN; and ceafes alto-
gether in the Winter.
II. That it is great in the MORNING;
diminished at MID-DAY; and little or
none in the EVENING.
III. That when the Vine, however, is
young and very vigorous, the Sap flows
inceffantly, and fastest of all in the
GREATEST HEAT OF THE DAY; fink-
ing only after SUN-SET,
{A Note to fhew the Value of this laft Obfervation,
The fame may be faid refpecting the IRRI-
TABILITY of the Hedyfarum Gyrans, and
the Senfitive Plant,
Hence it is, that the Return of Cold and
Froft in the SPRING is fo noxious to vege-
tables, and that THIS SEASON is generally
forward according to the Severity of the
preceding Winter,
412
413
SPALANZANI
SPALANZANI obferves that Newts bury them- felves and become torpid, when the Ther- mometer in AUTUMN is at 54; and again re-appear in SPRING, when the Thermo- meter is confiderably below 54,
FONTANA obferves, that when in SPRING he
exposed the Vipers that were torpid to the
Heat of 67 Degrees only they died, though
during SUMMER they bear a much greater
Degree of Heat without the leaft Injury,
Thus precifely it is with the vegetable Tribe,
for they fleep in Winter, and are awakened
by the vernal Sun; but die if a too power-`
ful Heat be fuddenly applied,
[On this Principle we may account for the De-
ftruction of Plants by BLIGHT in Spring;
for unless there be Froft at Night, and on
the next Day a cloudless Sun, there is no
Blight,
Hence if Plants be watered before the Rifing
414
415
of the Sun, they fuffer no Injury by the
previous Froft at this Seafon of the Year, - ib.
The Effects of Winter are therefore very great
in cold Climates, because the ACCUMULA-
TION OF IRRITABILITY is in proportion to
the Abstraction of the Stimulus of Heat,
Hence
Hence Corn ripens in LAPLAND in 60 Days,
whereas in FRANCE it requires 120 to 160
Days, -
SECT. XXXVIII.
THE MANNER IN WHICH
COLDS AND INFLAMMATORY FE-
VERS ARE PRODUCED.
{Of the Cold Bath,
The Cold Bath produces a great quiefcence of
the Capillaries of the Skin, the minute
Veffels of the Lungs, and their various ab-
forbent Series,
From their Quiefcence, occafioned by the want
of the Stimulus of Heat, the IRRITABLE
PRINCIPLE becomes ACCUMULATED, and
hence a greater Quantity of Blood is tranf-
mitted through them, and in confequence
a greater Degree of Heat enfues, - - -
The Reason why the COLD BATH is fre-
quently of great Service,
416
417
Of the Exception, and the Manner to obviate the Evil of COLD-BATHING,
An Experiment made by a healthy young
Man, who firft went into a Cold Bath,
where he ftaid 34 Minutes, and then
plunged into a Warm Bath at 90 Degrees, 418
Here,
Here, for the firft Moments, he felt very
warm, but in two Minutes, being still in
the Warm Bath, he was feized with Shi-
verings,
419
When he came out of the Warm Bath he
went to Bed, paffed a very feverish Night,
and the next Day had wandering Pains
over his Body, with great Weakness re-
fembling the incipient Stage of a FEVER, b.
Now, it can make little Difference, whether
a Person pass from cold Air or cold Water,
into warm Air or warm Water,
b.
fI have often seen, says Dr. BEDDOES, Perfons
who had long been riding in the Cold and
Wet, experience the firft Symptoms of FE- VER upon coming into a Warm Room, fit- ing near the Fire, and drinking Spirits, ib.
Dr. BEDDOES's own Experience, and the Man-
ner he has prevented the Acceffion of
FEVER,
A fingular Cafe arifing from the alternate Action of Cold and Heat producing INFLAM- MATION,
Mr. CLARKSON, in fetting forth the Impolicy
of the SLAVE TRADE, relates, that the
Seamen, to make Room for thefe unfor-
tunate Beings, from the Time of their
leaving the Coaft of Africa, fleep for the
moft Part on the Decks,
420
421
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