To let blood by the incision of a vein is not new: but to practise this in almost every distemper is new. Again, to bleed younger people, and women, that are not pregnant, is of ancient use. But to attempt the same in children and old people, and in pregnant women, is not an old practice. For indeed the ancients judged, that the first and last stages of life were not able to bear this kind of remedy; and they were persuaded, that a pregnant woman, who had been thus treated, would miscarry. But afterwards experience proved, that none of these rules were universal, and that some other circumstances were rather to be regarded, by which the intention of the physician was to be directed. For the material point is not, what the age may be, or what is contained within the body, but what degree of strength there is. Upon this account if a young man is valetudinary, or a woman not with child be weak, bleeding is bad: for the remaining strength, is by this evacuation destroyed. Whereas to a stout boy, and a robust old man, and a strong pregnant woman, it may be used with safety. ’Tis true an unskilful physician may be greatly deceived in such patients: because there is commonly less strength at these times of life. And a pregnant woman stands in need of strength after her cure, to support not only herself, but her fœtus also. But whatever requires either attention of mind, or prudence, is not to be immediately rejected: since the excellency of the art here consists, not in numbering the years, nor in regarding conception alone, but in considering the strength, and collecting from thence, whether there will be left sufficient to support either a boy, or an old man, or two bodies at once in one woman. There is a difference also between bodies strong, and corpulent: and those, that are slender, and infirm. In the slender, blood more abounds, but in those of a fuller habit, flesh. Wherefore the first bear this evacuation more easily: and he, that is over fat, is soonest distressed by it. For this reason the strength of the body is to be estimated rather by the state of the vessels, than from its appearance.

Nor are these the only particulars to be considered, but also what kind of distemper it is: whether a redundancy, or deficiency of matter has been hurtful; whether the body be corrupted or sound. For if there be a deficiency, or the humours be sound, this method is prejudicial. But if either the quantity of matter is hurtful, or it is corrupted, no other remedy is more successful; for this reason a violent fever, when the skin is red, and the veins are full and turgid, requires bleeding: likewise diseases of the bowels, and palsies, and the tetanus, and convulsions; in fine, whatever strangulates the fauces, so as to cause a difficulty in breathing; whatever suddenly stops the speech; any pain, that is intolerable; and any internal rupture, or bruise, from whatever cause; also a bad habit of body; and all acute distempers; provided, as I observed above, they hurt not by weakness, but by redundancy.

But it may possibly happen, that a distemper may indeed require this method, and at the same time the body may seem hardly able to bear it: but yet if there appears no other remedy, and the patient must perish, unless he shall be relieved even by a rash attempt; in this case, it is the part of a good physician to shew, that there is no hope without bleeding; and to confess what bad consequences may be apprehended even from that remedy; and after that, to bleed if desired. It is by no means proper to hesitate about it in such a situation as this: for it is better to try a doubtful remedy, than none at all. And this ought especially to be practised, when there is a palsy; when one has lost his speech suddenly; when an angina suffocates; when the preceding paroxysm of a fever has almost killed a person, and another equally severe is likely to follow, and the strength of the patient seems unable to bear it.

Though bleeding ought not to be performed in a state of crudity, yet even that does not hold always. For the circumstances will not at all times wait for concoction. So that if any person has fallen front a height, or has received a contusion, or vomits blood from some sudden accident, although he has taken food a little before, yet that evacuation is proper, lest if the matter settle, it distress the body. The same rule will hold in other sudden cases too, where there is a danger of suffocation. But if the nature of the distemper will allow a delay, it must not be done, till all remaining suspicion of crudity is removed. Upon this account, the second or third day of an illness seems most proper for this operation. But as sometimes it is necessary to bleed even on the first day, so it is never good after the fourth, when by time alone, the matter is either dissipated, or has corrupted the body; so that the evacuation may weaken, but cannot make it sound. But when a vehement fever prevails, to bleed in the time of its violence is killing the patient. Therefore an intermission(17) is to be awaited for: if it does not intermit, when it has ceased to increase: if there be no hopes even of a remission, in that case the only opportunity offered, though less favourable, is not to be neglected.

Further this remedy, where it is necessary, generally were best to be divided into two days; for it is better at the first to lighten the patient, and after that to cleanse him thoroughly, than to run any risk of his life by dissipating all his strength at once. And if this method be found to answer in the cure of a dropsy, how much more must it of necessity answer with regard to the blood?

If the disorder be in the whole body, the evacuation ought to be made from the arm: if in any particular place, from the part affected, or at least as near to it as may be; because it cannot be performed every where, but only in the temples, and in the arms, and near the ancles. I am not ignorant, that it is the opinion of some, that blood should be let at the greatest distance from the part where it does harm; for that thus the course of the matter is diverted; but in the other way it is drawn into that very place, which is distressed. But this is altogether false. For it first empties the part nearest: and the blood flows from the more remote, as long as the evacuation is continued: when this is stopt, because there is no more attraction, it then ceases to come. Yet experience itself seems to have shewn, that in a fracture of the skull blood is to be let rather from the arm: and if the disorder is in one arm, it must be performed in the other: I suppose for this reason, because if any miscarriage should happen, those parts, which are already hurt(18), are more exposed to injuries. Sometimes also an hæmorrhage breaking out in one part, is stopt by bleeding in another. For it ceases to flow, where we would not have it, when we apply what will stop its course there, and open another passage for it.

Altho’ bleeding is very easy to one, who has experience; yet it is very difficult to one, that is ignorant. For the vein lies close to the arteries; and to these the nerves. So that if the lancet has touched a nerve, a convulsion will follow, which destroys a man miserably. And then a wounded artery neither unites again, nor heals; and sometimes it occasions a violent hæmorrhage. If also the vein itself happens to be cut quite through, the two ends are compressed, and discharge no blood. Again, if the lancet is entered with fear, it lacerates the surface of the skin, and does not open the vein. Sometimes too the vein lies concealed, and is not easily found. Thus many circumstances make that difficult to an ignorant person, which is very easy to the skilful.

The vein is to be cut at the middle. And when the blood flows from it, its colour and consistence ought to be observed. For if it be thick and black, it is bad; and therefore the discharge is useful: if red and pellucid, it is sound; and that evacuation is so far from being beneficial, that it may even hurt, and is immediately to be stopt. But such an accident cannot happen to the physician, who knows in what case bleeding is to be used. It more commonly happens, that it flows on the first day equally black thro’ the operation. And altho’ it be so, yet if the discharge is sufficient, it must be stopt: and an end must always be put to it, before the person faints.

Then the arm is to be bound up, putting upon it a penecillum(19) dipt in cold water, and squeezed; and on the following day, the vein must be rubbed with the middle finger, that its recent union may be resolved, and it may again discharge blood. Whether it happens on the first or second day, that the blood, which at first flowed thick, and black, has begun to appear red and pellucid, there is then a sufficient quantity taken away, and what remains is pure: so that the arm is to be immediately bound up, and kept so, till the cicatrice is firm; which firmness it very soon acquires in a vein.