XVI. Much has been said likewise about the proper time for bleeding in fevers. It may be used at all times, when indicated by the pulse and other circumstances, in continual fevers; but it should be used chiefly in the paroxysms of such as intermit. I have conceived this practice to be of so much consequence, that, when I expect a return of the fever in the night, I request one of my pupils to sit up with my patients all night, in order to meet the paroxysm, if necessary, with the lancet. But I derive another advantage from fixing a centinel over a patient in a malignant fever. When a paroxysm goes off in the night, it often leaves the system in a state of such extreme debility, as to endanger life. In this case, from five to ten drops of laudanum, exhibited by a person who is a judge of the pulse, obviate this alarming debility, and often induce easy and refreshing sleep. By treating the human body like a corded instrument, in thus occasionally relaxing or bracing the system, according to the excess or deficiency of stimulus, in those hours in which death most frequently occurs, I think I have been the means of saving several valuable lives.
XVII. The different positions of the body influence the greater or less degrees of relief which are obtained by blood-letting. Where there is a great disposition to syncope, and where it is attended with alarming and distressing circumstances, blood should be drawn in a recumbent posture, but where there is no apprehension or dread of fainting, it may be taken in a sitting posture. The relief will be more certain if the patient be able to stand while he is bled. A small quantity of blood, drawn in this posture, brings on fainting, and the good effects which are often derived from it. It should therefore be preferred, where patients object to copious or frequent bleedings. The history of the success of this practice in the British army, recently mentioned from Dr. Sydenham, furnishes a strong argument in its favour.
I regret that the limits I have fixed to this Defence of Blood-letting will not admit of my applying the principles which have been delivered, to all the inflammatory states of fever. In a future essay, I hope to establish its efficacy in the maniacal state of fever. I have said that madness is the effect of a chronic inflammation in the brain. Its remedy, of course, should be frequent and copious blood-letting. Physical and moral evil are subject to similar laws. The mad-shirt, and all the common means of coercion, are as improper substitutes for bleeding, in madness, as the whipping-post and pillory are for solitary confinement and labour, in the cure of vice. The pulse should govern the use of the lancet in this, as well as in all the ordinary states of fever. It is the dial-plate of the system. But in the misplaced states of fever, the pulse, like folly in old age, often points at a different mark from nature. In all such cases, we must conform our practice to that which has been successful in the reigning epidemic. A single bleeding, when indicated by this circumstance, often converts a fever from a suffocated, or latent, to a sensible state, and thus renders it a more simple and manageable disease.
It is worthy of consideration here, how far local diseases, which have been produced by fevers, might be cured by re-exciting the fever. Sir William Jones says, the physicians in Persia always begin the cure of the leprosy by blood-letting[61]. Possibly this remedy diffuses the disease through the blood-vessels, and thereby exposes it to be more easily acted upon by other remedies.
Having mentioned the states of fever in which blood-letting is indicated, and the manner in which it should be performed, I shall conclude this inquiry by pointing out the states of fever in which it is forbidden, or in which it should be cautiously or sparingly performed. This subject is of consequence, and should be carefully attended to by all who wish well to the usefulness and credit of the lancet.
1. It is forbidden in that state of fever, as well as in other diseases, in which there is reason to believe the brain or viscera are engorged with blood, and the whole system prostrated below the point of re-action. I have suggested this caution in another place[62]. The pulse in these cases is feeble, and sometimes scarcely perceptible, occasioned by the quantity of blood in the blood-vessels being reduced, in consequence of the stagnation of large portions of it in the viscera. By bleeding in these cases, we deprive the blood-vessels of the feeble remains of the stimulus which keep up their action, and thus precipitate death. The remedies here should be frictions, and stimulating applications to the extremities, and gentle stimuli taken by the mouth, or injected into the bowels. As soon as the system is a little excited by these remedies, blood may be drawn, but in small quantities at a time, and perhaps only by means of cups or leaches applied to the seats of the congestions of the blood. After the vessels are excited by the equable diffusion of the blood through all their parts, it may with safety be drawn from the arm, provided it be indicated by the pulse.
2. It is seldom proper beyond the third day, in a malignant fever, if it has not been used on the days previous to it, and for the same reason that has been given under the former head. Even the tension of the pulse is not always a sufficient warrant to bleed, for in three days, in a fever which runs its course in five days, the disorganization of the viscera is so complete, that a recovery is scarcely to be expected from the lancet. The remedies which give the only chance of relief in this case, are purges, blisters, and a salivation.
3. Where fevers are attended with paroxysms, bleeding should be omitted, or used with great caution, in the close of those paroxysms. The debility which accompanies the intermission of the fever is often so much increased by the recent loss of blood, as sometimes to endanger life.
4. Bleeding is forbidden, or should be used cautiously in that malignant state of fever, in which a weak morbid action, or what Dr. Darwin calls a tendency to inirritability, takes place in the blood-vessels. It is known by a weak and frequent pulse, such as occurs in the typhus fever, and in the plague in warm climates. I have often met with it in the malignant sore throat, and occasionally in the pleurisy and yellow fever. The remedies here should be gentle vomits or purges, and afterwards cordials. Should the pulse be too much excited by them, bleeding may be used to reduce it.
5. It should be used sparingly in the diseases of habitual drunkards. The morbid action in such persons, though often violent, is generally transient. It may be compared to a soap-bubble. The arteries, by being often overstretched by the stimulus of strong drink, do not always contract with the diminution of blood, and such patients often sink, from this cause, from the excessive use of the lancet.