By making use of blood-letting in fevers, we are not precluded from the benefits of the other evacuating remedies. Some of them are rendered more certain and more effectual by it, and there are cases of fever, in which the combined or successive application of them all is barely sufficient to save life.
To rely upon any one evacuating remedy, to the exclusion of the others, is like trusting to a pair of oars in a sea voyage, instead of spreading every sail of a ship.
I suspect the disputes about the eligibility of the different remedies which have been mentioned, have arisen from an ignorance that they all belong to one class, and that they differ only in their force and manner of operation. Thus the physicians of the last century ascribed different virtues to salts of different names, which the chemists of the present day have taught us are exactly the same, and differ only in the manner of their being prepared.
Having replied to the principal objections to blood-letting, and stated its comparative advantages over other modes of depletion, I proceed next to mention the circumstances which should regulate the use of it. These are,
I. The state of the pulse.
The following states of the pulse indicate the necessity of bleeding.
1. A full, frequent, and tense pulse, such as occurs in the pulmonary, rheumatic, gouty, phrenitic, and maniacal states of fever.
2. A full, frequent, and jerking pulse, without tension, such as frequently occurs in the vertiginous, paralytic, apoplectic, and hydropic states of fever.
3. A small, frequent, but tense pulse, such as occurs in the chronic, pulmonary, and rheumatic states of fever.
4. A tense and quick pulse, without much preternatural frequency. This state of the pulse is common in the yellow fever.