They are divided into various classes; though in fact all of one nature. When the ague with its succeeding fever comes on regularly every day, it is called _quotidian_, or every day’s ague; when every second day, _tertian_, or third day’s ague, and when every third day; a _quartan_, or fourth day’s ague. There are many other classes as subdivisions of these, but they are the mere speculations of physical pedants, who are ever sworn enemies to plain understanding, and delight in perplexities; which therefore, we shall neither spend paper nor time upon to recount. Suffice it, let their paroxysms return at what stated period of time they will, either regularly or irregularly, they differ in nothing but this, that the farther the fits are distanced, the severer they generally are, when they come on; and the more regular, the more obstinate in their cure; though in this even there are exceptions. It is surprizing to imagine, how many different opinions have been sent into the world concerning the returns of the periodical fits of the ague; and equally astonishing, how few with any probability of truth or reason. I shall not here enter into an enquiry of this nature; certain it is, that at the stated times of these returning fits of the ague, there is an obstruction in some particular part of the system, that corresponds with the dated time of the circulation of fluids in such parts—which when disturbed, effects by the nervous consent, the whole animal structure. The principal intention in all intermitting fevers, should be to correct the petuity and acrimony of the blood; to remove the obstructions; and to strengthen the solids. With respect to the blood, it is an inevitable consequence, that when it is loaded with a vicidity and lentor, that it will ever occasion a depraved nutrition; and hence we see, that people labouring under agues, and intermittent fevers of any kind, have a depraved appetite, and many disagreeablenesses in the first passages. The intermittent fever and ague approach with the following symptoms, viz. a heavy dull head-ach, a shivering chill all over the body, with a yawning, &c. pain in all the limbs attended with weariness, a nausea at the stomach, a depressed pulse; which after it has lasted for half an hour, changes into a burning heat, a throbbing head-ach, pain in the loins, and in every limb, a great draught, a _full hard pulse_, and which at last terminates in a profuse sweat; this seems to give the patient ease, for one, two, or three days; and then attacks the patient with the same symptom, increasing every time, and reduces the patient both in body and spirit. The first thing to be done is to give a vomit, like No. XV. and XXVI. This is best taken at the approach of the cold fit, and worked well off with plenty of luke warm water. After the operation of the vomit is over, let the patient take the following draught. No. XXVII