I regret that the limits I have fixed to this Defence of Blood-letting will not admit of my applying the principles which have been delivered, to all the inflammatory states of fever. In a future essay, I hope to establish its efficacy in the maniacal state of fever. I have said that madness is the effect of a chronic inflammation in the brain. Its remedy, of course, should be frequent and copious blood-letting. Physical and moral evil are subject to similar laws. The mad-shirt, and all the common means of coercion, are as improper substitutes for bleeding, in madness, as the whipping-post and pillory are for solitary confinement and labour, in the cure of vice. The pulse should govern the use of the lancet in this, as well as in all the _ordinary_ states of fever. It is the dial-plate of the system. But in the _misplaced_ states of fever, the pulse, like folly in old age, often points at a different mark from nature. In all such cases, we must conform our practice to that which has been successful in the reigning epidemic. A single bleeding, when indicated by this circumstance, often converts a fever from a suffocated, or latent, to a sensible state, and thus renders it a more simple and manageable disease. It is worthy of consideration here, how far local diseases, which have been produced by fevers, might be cured by re-exciting the fever. Sir William Jones says, the physicians in Persia always begin the cure of the leprosy by blood-letting[61]. Possibly this remedy diffuses the disease through the blood-vessels, and thereby exposes it to be more easily acted upon by other remedies. [61] Asiatic Essays. Having mentioned the states of fever in which blood-letting is indicated, and the manner in which it should be performed, I shall conclude this inquiry by pointing out the states of fever in which it is forbidden, or in which it should be cautiously or sparingly performed. This subject is of consequence, and should be carefully attended to by all who wish well to the usefulness and credit of the lancet.