Here, as upon a former occasion, we may say with concern, if bleeding be indicated by all the appearances of the blood which have been enumerated, how many lives have been lost by physicians limiting the use of the lancet to those cases only, where the blood discovered an inflammatory crust!
These remarks upon the relative signs of inflammatory action in the blood-vessels, should be admitted with a recollection that they are all liable to be varied by a moderate, or violent exacerbation of fever, by the size of the stream of blood, and by the heat, coldness, and form of the cup into which the blood flows. Even blood drawn, under exactly equal circumstances, from both arms, exhibited, in a case of pleurisy communicated to me by Dr. Mitchell, of Kentucky, very different appearances. That which was taken from one arm was sizy, while that which was taken from the other was of a scarlet colour. That which is drawn from a vein in the arm, puts on, likewise, appearances very different from that which is discharged from the bowels, in a dysentery. These facts were alluded to in the Outlines of the Theory of Fever[56], in order to prove that unequal excitement takes place, not only in the different systems of the body, but in the same system, particularly in the blood-vessels. They likewise show us the necessity of attending to the state of the pulse in both arms, as well as in other parts of the body, in prescribing blood-letting. When time, and more attention to that index of the state of the system in fevers, shall have brought to light all the knowledge that the pulse is capable of imparting, the appearances of the blood, in fevers, will be regarded as little as the appearances of the urine.
XI. Blood-letting should always be copious where there is danger from sudden and great congestion or inflammation, in vital parts. This danger is indicated most commonly by pain; but there may be congestion in the lungs, liver, bowels, and even in the head, without pain. In these cases, the state of the pulse should always govern the use of the lancet.
XII. What quantity of blood may be taken, with safety, from a patient in an inflammatory fever? To answer this question it will be necessary to remark, 1. That, in a person of an ordinary size, there are supposed to be contained between 25 and 28 pounds of blood; and 2. That much more blood may be taken when the blood-vessels are in a state of morbid excitement and excitability, than at any other time. One of the uses of the blood is to stimulate the blood-vessels, and thereby to assist in originating and preserving animal life. In a healthy state of the vessels, the whole mass of the blood is necessary for this purpose; but in their state of morbid excitability, a much less quantity of blood than what is natural (perhaps in some cases four or five pounds) are sufficient to keep up an equal and vigorous circulation. Thus very small portions of light and sound are sufficient to excite vision and hearing in an inflamed, and highly excitable state of the eyes and ears. Thus too, a single glass of wine will often produce delirium in a fever in a man, who, when in health, is in the habit of drinking a bottle every day, without having his pulse quickened by it.
An ignorance of the quantity of blood which has been drawn by design, or lost by accident, has contributed very much to encourage prejudices against blood-letting. Mr. Cline drew 320 ounces of blood in 20 days from a patient in St. Thomas's hospital, who laboured under a contusion of the head. But this quantity is small compared with the quantity lost by a number of persons, whose cases are recorded by Dr. Haller[57]. I shall mention a few of them. One person lost 9 pounds of blood, a second 12, a third 18, and a fourth 22, from the nose, at one time. A fifth lost 12 pounds by vomiting in one night, and a sixth 22 from the lungs. A gentleman at Angola lost between 3 and 4 pounds daily from his nose. To cure it, he was bled 97 times in one year. A young woman was bled 1020 times in 19 years, to cure her of plethora which disposed her to hysteria. Another young woman lost 125 ounces of blood, by a natural hæmorrhage, every month. To cure it, she was bled every day, and every other day, for 14 months. In none of these instances, was death the consequence of these great evacuations of blood. On the contrary, all the persons alluded to, recovered. Many similar instances of the safety, and even benefit of profuse discharges of blood, by nature and art, might be mentioned from other authors. I shall insert only one more, which shall be taken from Dr. Sydenham's account of the cure of the plague. “Among the other calamities of the civil war which afflicted this nation, the plague also raged in several places, and was brought by accident from another place to Dunstar Castle, in Somersetshire, where some of the soldiers dying suddenly, with an eruption of spots, it likewise seized several others. It happened at that time that a surgeon, who had travelled much in foreign parts, was in the service there, and applied to the governor for leave to assist his fellow-soldiers who were afflicted with this dreadful disease, in the best manner he was able; which being granted, he took so large a quantity of blood from every one at the beginning of the disease, and before any swelling was perceived, that they were ready to faint, and drop down, for he bled them all standing, and in the open air, and had no vessel to measure the blood, which falling on the ground, the quantity each person lost could not, of course, be known. The operation being over, he ordered them to lie in their tents; and though he gave no kind of remedy after bleeding, yet of the numbers that were thus treated, not a single person died. I had this relation from Colonel Francis Windham, a gentleman of great honour and veracity, and at this time governor of the castle[58].”
Again. An ignorance of the rapid manner in which blood is regenerated, when lost or drawn, has helped to keep up prejudices against blood-letting. A person (Dr. Haller says) lost five pounds of blood daily from the hæmorrhoidal vessels for 62 days, and another 75 pounds of blood in 10 days. The loss each day was supplied by fresh quantities of aliment.
These facts, I hope, will be sufficient to establish the safety and advantages of plentiful blood-letting, in cases of violent fever; also to show the fallacy and danger of that practice which attempts the cure of such cases of fever, by what is called moderate bleeding. There are, it has been said, no half truths in government. It is equally true, that there are no half truths in medicine. This half-way practice of moderate bleeding, has kept up the mortality of pestilential fevers, in all ages, and in all countries. I have combated this practice elsewhere[59], and have asserted, upon the authority of Dr. Sydenham, that it is much better not to bleed at all, than to draw blood disproportioned in quantity to the violence of the fever. If the state of the pulse be our guide, the continuance of its inflammatory action, after the loss of even 100 ounces of blood, indicates the necessity of more bleeding, as much as it did the first time a vein was opened. In the use of this remedy it may be truly said, as in many of the enterprizes of life, that nothing is done, while any thing remains to be done. Bleeding should be repeated while the symptoms which first indicated it continue, should it be until four-fifths of the blood contained in the body are drawn away. In this manner we act in the use of other remedies. Who ever leaves off giving purges in a colic, attended with costiveness, before the bowels are opened? or who lays aside mercury as a useless medicine, because a few doses of it do not cure the venereal disease?
I shall only add under this head, that I have always observed the cure of a malignant fever to be most complete, and the convalescence to be most rapid, when the bleeding has been continued until a paleness is induced in the face, and until the patient is able to sit up without being fainty. After these circumstances occur, a moderate degree of force in the pulse will gradually wear itself away, without doing any harm.