This section is from the book "The London Medical Dictionary", by Bartholomew Parr. Also available from Amazon: London Medical Dictionary.
Tas; electricity, (from amber). The quality which amber possesses of attracting light bodies when rubbed, has expanded into consequences the most extensive, and results the most important: it has become the science of electricity; has drawn thunder from the clouds; and, in the hands of philosophers, may deprive earthquakes of their destructive power. Our province is more humble: it is to trace its powers in a little microcosm, in a limited circle, where we once hoped to find it a salutary guardian; but where it appears only, if not a harmless, at least not a beneficial agent.
We must not detail the principles of this science, or enlarge on contending systems. It will simplify our language if we consider positive electricity as the ex-cess, and negative as a deficiency, of this fluid: the former as the excess of uncombined electricity, the latter as a deprivation of the due or necessary quantity. A theory of this kind we could render equally probable with any other; but it is unnecessary, since the facts may be readily translated into a more fashionable language, if such a translation be required.
In the view we have just offered, each body has its proportionate share of this fluid, which may be increased or diminished; but, in either case, the equilibrium is only restored with some violence, called a shock; though it may more silently take place by appropriate means, to be afterwards described. This share is determined by the nature of the body; but is, in general, greater or less as the body is a conductor or a non-conductor; i. e. that it has a power of conducting any excess of el< city to its common reservoir, the earth, or of confining it to its own substance. Thus metals and fluids are powerful conductors; any dry bodies, particularly vitreous ones, non-conductors. The human body is, in general, a conductor, as consisting of fluids, and communicating with the earth by its surface, commonly moistened by the perspiration.
It has been rendered highly probable, by an anonymous author, in a collection of essays (Exeter Essays), that, on the conversion of any fluid to an aerial form, the electrical escapes; and, on the contrary, that v. air is converted to a fluid, that it disappears; probably, in the first instance, separated from, and in the combined with, the fluid. If this-be true, in meteorological phenomena, as it seems to be. from a very careful induction from facts, it probably is so in physiology; and it is supported by some striking appearances. Thus the electricity of the human body, in its healthy state, is, like that of the generality of bodies, positive: such also is the electricity of the blood; but, in the animal economy, various functions continually go on, in which air is separated and carried off. The electricity, therefore, of the body must be constantly changing; and we, of course, find, as may be expected, that of some of the fluids negative. Such is the electricity of all the ex-crementitious fluids.
Again: We know that in confined air, in heated and crowded rooms, these aerial changes are more considerable; and it is consequently not uncommon, in such circumstances, to find the electricity of the whole body negative. Such observations have, unfortunately, not been duly examined, and we must take advantage of incidental facts. The ignis fatuus is, we know, inflammable air ignited by electricity. It flies from a person who pursues it, because the electricity of each is positive; but Dr. Priestley has recorded an observation, where it seemed to follow the person, who had been long in a crowded room; and we learn from Mr. Read, (Phil. Transactions for 1794) that the electricity of the air, in such an apartment, probably from the perspirations of a numerous assemblv, is negative. We may-conclude, then, that the positive electricity of the body disappears in the animal process; but nothing is lost. It, perhaps, performs a most important office, which we can only at present guess at; but this is scarcely a place for conjecture. Let us. however, at once hazard it. The electrical fluid, by its union, elicits heat (Pictet sur Ie Feu, 108); and this fluid is nearly and intimately connected with the nervous power. The one is probably occasioned, and the other supported, by the electricity that disappears.
If a resinous, as well as a Vitreous, electricity exist, in other words, two fluids of different and opposite properties, the distinction appears to be immaterial in a medical view. Each produces similar effects when used as a remedy, and this consideration led us to adopt the simple language with which we introduced the subject.
Electricity is employed in medicine chiefly when accumulated. If the communication with the earth is cut off, and the fluid accumulated in the body by the action of a proper machine, it is called simple electricity. If then the fluid is drawn off, silently, by points, or more actively by rounded conductors, the electric aura, or electric sparks,are said to be drawn. If the accumulated electricity be at once discharged, or, in other language, if the communication between the different sides of the electrical jar be suddenly restored, the shock is said to be produced. Electricity, in each instance, acts as a stimulus only. Simple electricity increases the circulation, accelerates the jet of blood in bleeding, increases
4 G 2 perspiration, as well as the other secretions and the appetite. When the aura is gently drawn off, a slight stimulus augments the action of the vessels, from which it is taken; when by rounded conductors, in the form of sparks, the stimulus is more considerable. When the equilibrium is suddenly restored, every fibre seems agitated. When slight it is felt in the fingers and wrists only; when gradually more violent, the shock affects the elbows, the arms, and the chest. This happens when the equilibrium is restored, by touching the conductor with each hand; and, in this case, the fluid takes the shortest circuit, through the arms and breast, apparently passing through the nerves; for its effects are chiefly felt where they are more strictly tied down by their sheaths. When the stimulus is wanted in any particular part, the conductors are so placed as to convey the fluid necessary to restore the equilibrium through that part. The effects of the shock are said to be stimulant; but it is rather a violent concussion, without any discriminated or permanent change. It may be made so strong as to kill smaller animals; and, for a time, to deprive even a human being of his senses. When animals are killed by it, the irritability of the muscles is destroyed, an effect also occasioned by hydrogen: sometimes an important blood vessel is ruptured. If the shock be a stimulus, and destroy by excess of excitement, we might expect, that, in a less degree, it would prove useful as such. It undoubtedly excites the action of a paralysed muscle, but produces no permanent good effect; so that this mode of employing electricity is now almost wholly disused.
In general, then, electricity must be considered as a simple stimulant; and it increases all the actions going on in the system, whether salutary or morbid. It promotes suppuration, and more firmly impacts the fluids in infarcted glands. But it also discusses tumours not too firmly fixed, and assists the recovery of the nervous power of a debilitated organ.
From this view of the subject, it will be obvious that electricity is chiefly useful in asthenic diseases, and in obstructions not yet insurmountable. It must be hurtful in inflammatory disorders; where, with an inflammatory diathesis, there is a strong determination to any part; when the irritability is considerable, or the obstruction firm, and of long standing.
In febrile diseases, it has been seldom employed, except to terrify on the approach of intermittents; when, by the unexpected shock, it often succeeds.
In inflammations, it has been sometimes employed to discuss phlegmons; occasionally to relieve ophthalmiae. In both cases the shocks are inadmissible. In the former sparks may be drawn; but, in the latter, the points must be used to solicit the aura. In the tooth ach it has been also sometimes employed, as well as in the gout and in inflammatory cynanche, but with very little effectual relief; and it is now, in general, disused.
The chief complaints in which advantage from electricity has been expected are the palsies. It was first used at Geneva; and was said to have cured a locksmith and one other person of haemiphlegiac. It is now well known, that the relief obtained by each was temporary only; and though it continues to be employed, generally in the form of shocks, its utility is inconsiderable and temporary. In many instances it has certainly been injurious.
In the more partial palsies, drawing sparks has been occasionally beneficial, though in no considerable degree: and the power of debilitated organs, as of the eye in gutta serena; of the ear in deafness; or of a palsied muscle, has been sometimes, in part, restored. Electricity has been also tried in chronic rheumatism, a species of palsy, and in anaenorrhaea. Slight shocks, in each, have been sometimes useful. In the last complaint, the fluid must be directed through the pelvis. We have sometimes succeeded in procuring a return of the menses by these means; but we have more often produced leucorrhcea. Electricity has been also often employed to restore suspended animation from apparent drowning, and is supposed to be a powerful and effectual remedy; but we have never found it of the slightest use. A physician at Brunswick, M. Friske, has directed the shocks, through the abdomen, to kill the tape worm; in which he thinks he has succeeded. On recurring to the authors on medical electricity, in almost all we observe a very prudent remark, that during its course the proper medicines are by no means to be omitted.