plaints as they had lately enjoyed, and for fo confiderable a time, they believed themselves perfectly cured.

I have been also informed, from the best authority, that during the troubles in Scotland, in the years 1745 and 1746, hysterical and nervous diforders fcarcely ever

made their

A

appearance.

very remarkable inftance of the influence the mind has upon diforders of the body occurred to the celebrated BOERHAAVE. A perfon fell down in an epileptic fit in the fight of the other patients. The effect of this operated so strongly, that great numbers of them became immediately affected in the fame manner. The opinion of the great phyfician above mentioned was requested on this occafion. He judicioufly reflected, that, as these fits were originally produced by an impreffion on the mind, that the inoft proper means of cure would be to eradicate thefe impreffions by others still more powerful. He therefore directed actual cauteries to be prepared, and kept hot, in readiness to be applied to the person who fhould next be affected. The confequence was, not one perfon was feized.

A gentleman of great courage and honour, who had become valetudinary, and subject to the asthma, by long fervice in India, as an officer in the land forces, tald me,

he was attacked with a fevere fit of that disorder during their encampment, which ufually lafted from ten to twelve days: that, upon the third or fourth day of his illness, when he could only breathe in an erect posture, and without motion, imagining that it was not in his power to move fix yards to fave his life, the alarm guns were fired for the whole line to turn out, because a party of the Mahrattas had broke into the camp; and fearing certain death if he remained in his tent, he fprung out with an alacrity that amazed his attendants; inftantly mounted his horfe, and drew his fword with great cafe, which the day before he could not move from its fcabbard, though he had used his whole firength in the attempt. From the inftant of the alarm and furprise, the debility left him, together with the asthma; nor did the diforder return for fome time after.

SECT.

SECT. XXIX.

OF HABIT.

A PROPENSITY to acquire habits, and to act from them, when the original incentive has long fince ceased, is a general law of the animal ceconomy, which though fometimes the fource of evil, is in the great tenor of life productive of much good.

The favage may fait many hours and then` feed voracioufly, without fuffering either by inanition or repletion but they who, in civilized society, have acquired the habit of eating five times every day, cannot pafs one meal, nor without impatience wait five minutes beyond the ufual time of eating. In both, the appetite for food and the powers of digeftion depend on habit.

In case of great mental excitement, a man may continue many days without repofe; but if he has acquired the habit of fleeping at a certain hour, and for a certain length of time, fleepiness at that hour will return, and at the accustomed hours he will awake from fleep.

Both the defire for fleep, and the difpofition to awake,

may, by habit, become as regular as the rifing and the fetting of the fun.

The fame holds good with respect to evacuations. I. had a nurse for my children, fays the fagacious author of the Guide to Health, who was fo perfectly fatisfied of this, that the governed them by the clock, and in their earliest infancy taught them the vast influence of habit.

By abstraction of fome of the neceffary ftimuli, as food, lofs of blood, exhausting diseases, indolence, and protracted fleep, the irritable fibres, from being elastic and robust, and patient of labour, become flaccid, tender, and liable to be foon fatigued.

A generous diet, with the affiftance of bark, chaly beates, cold bathing, and fufficient exercife, foon however restore the tone to the fibre. These several stimuli diftribute, impact, condenfe, and accumulate energy to every part; and bracing up the animated fibre, make it tenacious of vitality.

But when the fteel, and bark, and bathing, are left off, how is the impulfe to the movements conftituting health kept up?

Ans. The actions which thefe occafioned become affociated with the other actions in the frame, and though a link or two in the chain of motions be removed, the circle

U u

circle of motions will nevertheless proceed for a time in due order. Thus when a child revolves fome minutes on one foot, the spectra of ambient objects appear to circulate round him some time after he falls upon the ground. Thus the ftomach feels squeamish, and the objects dance about, to those who are just come on shore after a long voyage. Thus the palpitation of the heart continues fome time after the object of fear which occafioned it is removed. And thus the blufh of fhame, which is an excess of fenfation, and the glow of anger, which is an excess of volition, continue fome time, though the affected perfon finds, that those emotions were caused by mistaken facts, and even endeavours to extinguish their appearance.

Befides, during this interval of increased action, the difeafe is baffled, and the fibre is invigorated, and the conftitution being fet to rights, naturally continues to go on well by means of the natural ftimuli, which are fufficient for the purposes of the animal economy in a ftate of health.

Every part of the fyftem is, as we have feen, under the influence of habit, and even the mind itself is not exempt from it.

* Dr, DARWIN,

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