4. The synochus state of fever is known by a full, quick, and round pulse without tension. The autumnal bilious fever and colic, also the gout, often appear in this form.

5. There is a state of fever in which the pulse is small, but tense and quick. The patient, in this state of fever, is seldom confined to his bed. We observe it sometimes in the chronic rheumatism, and in pulmonary consumption. The inflammatory state of this grade of fever is proved from the inefficacy of the volatile tincture of guaiacum and other stimulants to remove it, and from its yielding so suddenly to blood-letting. I have called it the synochula state of fever.

6. There is a state of fever inclining more to the synocha, than what is called the typhus, or low chronic state of fever. I have called it the synochoid state of fever.

7. The typhus state of fever is generally preceded by all those circumstances which debilitate the system, both by the action and abstraction of stimuli. It is known by a weak and frequent pulse, a disposition to sleep, a torpor of the alimentary canal, tremors of the hands, a dry tongue, and, in some instances, by a diarrhœa. These symptoms occur most frequently in what is called the jail, the ship, and the hospital fever. I heard of it in a few cases in the yellow fever of 1793, and all writers take notice of cases of the plague, which run on into a slow fever that continues 30 or 40 days. I have seen it succeed the common bilious fever, pleurisy, and influenza. It has been confounded with the malignant state of fever, or what is called the typhus gravior; but it differs widely from it in being accompanied by a feeble excitement in the blood-vessels, from a feeble stimulus, and by the usual signs of debility from abstraction in every other part of the body.

From the accession of new stimuli, or an increase in the force of former ones, this typhus state of fever sometimes assumes, on the 11th, 14th, and even 20th days, the symptoms of the synocha state of fever. It will be useful to remember this remark, not only because it establishes the unity of fever, but because it will justify the use of a remedy, seldom prescribed after the disease has acquired that name which associates it with stimulating medicines.

The common name of this state of fever, is the nervous fever. This name is improper; for it invades the nervous system by pain, delirium, and convulsions much less than several other states of fever. To prevent the absurd and often fatal association of ideas upon the treatment of this state of fever, I have called it, from its duration, the low chronic state of fever. I have adopted the term low, from Dr. Butter's account of the remitting fever of children, in order to distinguish it from states of fever to be mentioned hereafter, in which the patient is not confined to his bed. This new name of the typhus or nervous fever establishes its analogy with several other diseases. We have the acute and the chronic rheumatism; the acute and chronic pneumony, commonly called the pleurisy and pulmonary consumption; the acute and chronic inflammation of the brain, known unfortunately by the unrelated names of phrenitis, madness, and internal dropsy of the brain. Why should we hesitate, in like manner, in admitting acute and chronic fever, in all those cases where no local inflammation attends?

8. The typhoid state of fever is composed of the synocha and low chronic states of fever. It is the slow nervous fever of Dr. Butter. The excitement of the blood-vessels is somewhat greater than in the low chronic state of fever. Perhaps the muscular fibres of the blood-vessels, in this state of fever, are affected by different degrees of stimulus and excitement. Supposing a pulse to consist of eight cords, I think I have frequently felt more or less of them tense or relaxed, according as the fever partook more or less of the synocha, or low chronic states of fever. This state of fever occurs most frequently in what are called the hectic and puerperal fevers, and in the scarlatina.

9. The hectic state of fever differs from all the other states of fever, by the want of regularity in its paroxysms, in which chills, fevers, and sweats are included; and by the brain, nerves, muscles, and alimentary canal being but little impaired in their functions by it. It appears to be an exclusive disease of the blood-vessels. It occurs in the pulmonary consumption, in some cases of lues, of scrophula, and of the gout, and after most of the states of fever which have been described. The force of the pulse is various, being occasionally synochoid, typhoid, and typhus.

10. Intermissions, or the intermitting and remitting states of fever, are common to all the states of fever which have been mentioned. But they occur most distinctly and universally in those which partake of the bilious diathesis. They have been ascribed to the reproduction of bile, to the recurrence of debility, and to the influence of the heavenly bodies upon the system. None of these hypotheses has explained the recurrence of fever, where the bile has not been in fault, where debility is uniform, and where the paroxysms of fever do not accord with the revolutions of any part of the solar system. I have endeavoured to account for the recurrence of the paroxysm of fever, in common with all other periodical diseases, by means of a natural or adventitious association of motions. Dr. Percival has glanced at this law of animal matter; and Dr. Darwin has explained by it, in the most ingenious manner, many natural and morbid actions in the human body.