Billeder på siden
PDF
ePub

self in a state of EXHAUSTION, and this exhaustion will

be either,

1. Temporary, or

2. Irreparable.

1. In the ftate of temporary exhaustion the fibre fails for want of IRRITABILITY. The application of the ordinary stimulus, while it is in this ftate, will not make it contract. It is only by little and little that the fibre recovers its IRRITABILITY. This truth, I dare venture to fay, is as new as it is ftriking, and it unfolds a vast number of phænomena hitherto inexplicable.

Let us obferve, for example, the tremulous writing of old men, or the motion of the heart;-the heart contracts from the ftimulus of the blood, and impels the blood through the arteries; it then again dilates, and the blood enters. But the heart does not contract itself immediately upon the first impreffion of the blood. Its IRRITABILITY having been leffened by the preceding contraction, it requires half, or three quarters of a fecond, before the IRRITABILITY of the heart fhall have been recruited to fuch a degree that the fame ftimulus can act upon it.

The periods of women are explained on the fame principle. The ftimulus of the ovaries acting continually in them after the age of puberty (as I fhall prove elsewhere),

elsewhere), nevertheless, does not produce its effects till the end of eight and twenty days; because this period of time is neceffary for the uterus, in its state of health, to accumulate its IRRITABILITY in fufficient quantity for the stimulus to act; the discharge ceases after the irritability of this organ has been diminished, and returns with the returning irritability.

Thus during the operation of an emetic or cathartic, the ftomach and bowels is alternately in a ftate of excitement and repose. And thus the most violent pains and labour of a parturient woman, if not effectual for the expulfion of the offspring, ceafe for a time, and are then renewed. Thus likewife all the appetites are liable to fits, returning after ceffation at stated periods; if it be hunger, at the distance of fome hours; if it be fever, it may be explained on the fame principle; that is to say, any stimulus which is always prefent, and continually acting upon the fibres, produces no fenfible effect, till the exhausted irritability of the fibre fhall have accumulated afresh.

You can scarcely touch the leaf of the mimofa pudica, or fenfitive plant, fo flightly as not to make it close. The large rib which runs along the middle of the leaf, ferves as an hinge on which the two halves of the leaf turn on being

8

being touched, till they ftand erect, and by that means meet one another. The flightest touch gives this motion to one leaf; if a little harder, it gives the fame motion to the leaf oppofite. If the touch be fill rougher, the whole arrangement of leaves on the fame rib close in the fame manner. If it be ftronger ftill, the rib itself moves upwards towards the branch on which it grows. And if the touch be yet more rough, the very branches shrink up towards the main stem.

In August, one of these plants growing in a pot was put into a carriage. The motion of the carriage caused it to shut up all its leaves, and the effect of this great fimulus was, that it did not again expand its leaves for more than four and twenty hours. A TORPOR then enfued for having opened their leaves, they closed no more for three days and as many nights.-Being then brought again into the open air, the leaves recovered their natural motions, shutting each night, and opening in the morning, as regularly as ever.

:

All the periodical motions of plants and animals, as well as their periodical difeafes, may be explained upon the fame principle; that is to fay, any ftimulus which is always prefent, and continually acting upon the fibre, produces no fenfible effect, till the exhaufted irritability

of the fibre fhall have been accumulated afresh. The periodical motions in organized bodies depend on the alternate exhaustion and accumulation of the irritability of the fibre. A temporary exhauftion of the irritability of the bedyfarum gyram is produced by the heat of the fun and by electricity. The electrical fluid exhaufts in like manner the irritability of the mimofa.

Let us confider the ftimulating or exciting power of wine. When a depressed man is infufficiently excited with the natural ftimuli, and rifes not, fuppofe, above 30 degrees in his excitement, a glafs carries him up tỏ 32 degrees, another to 34 degrees, and fo forth, till after five glaffes he is carried up to 40 degrees, he then finds himself well and vigorous in all his functions. But ftill we are not fo flimfily made, as not to bear a little of what is either too much or too little. Suppofe he then takes five glaffes more, and confequently is raised to 50 degrees. As his fpirits, his intellectual, and all his other functions, were low, while his excitement remained at 40 degrees, fo are they all proportionally exalted by the time that his excitement is elevated to 50 degrées. Let him ftill go on, and his intellectual functions will rife still higher; he will now difplay the full extent of his genius; and his paffions and emotions of

whatever

whatever kind they be.-If he goes on, how will the appearance be reverfed! The hero* foon fhrinks into a mere brute. He falls off in both his intellectual and corpo

* Vide the Elements of Phyfic. That JOHN BROWN perhaps caught the first idea of his philosophy from ARMSTRONG's Poem on the Art of Preferving Health, as before hinted, page 210 of this work, is in some measure confirmed, by comparing the above with the following lines. Speaking of the effects of wine, Dr. ARMSTRONG fays,

"Struck by the powerful charm, the gloom diffolves
"in empty air; Elyfium opens round.

"A pleafing phrenzy buoys the lighten'd soul,
"and fanguine hopes difpel your fleeting care;
"and what are difficult, and what was dire,
"yields to your prowess and superior stars:
"the happiest you, of all that e'er were mad,
❝or are, or shall be, could this folly laft.
"But foon your heaven is gone; a heavier gloom

"fhuts o'er your head: and, as the thundering ftream,
"fwoln o'er its banks with fudden mountain rain,
"finks from its tumult to a SILENT brook;

"fo, when the frantic raptures in your breaft

66 fubfide, you languish into mortal man ;

66 you SLEEP, and waking find yourself undone.

"FOR PRODIGAL OF LIFE IN ONE RASH NIGHT

"YOU LAVISH'D MORE THAN MIGHT SUPPORT THREE DAYS, "A heavy morning comes; your cares return

"with tenfold rage, &c.

Book IV.

It is not meant to derogate ought from the illuftrious founder of the new philofophy of medicine: JOHN BROWN will ever retain his advocates, and the rancour of his enemies will prove how far he was the original inventor of this beautiful and coherent system. Another might, at a chance time, like a meteor, fhine forth, but this light was foon loft in the thick gloom that overspread this branch of science; whereas, in the theoretical writings of JOHN BROWN, we fee the effulgence of the noon-day. And if he was not always practically just, we have to lament the shortness of his career of life, and the vaftness of that perfecution that was invidiously raised against him.

[blocks in formation]
« ForrigeFortsæt »