It is possible to view the action of blisters in neuralgia in more than one way. When applied in such a manner as to vesicate decidedly, and especially if kept open and suppurating for some time, they cause considerable pain of a different kind from that of neuralgia itself and the mental effect of this, operating as a diversion of the patient's thoughts from his original trouble, may be thought to assist in breaking the chain of nervous actions by which he is made to feel neuralgic pain. There may be something in this, but I confess that I do not believe this kind of effect goes for much in genuine neuralgia. It is rather in the pain of hypochondriasis, and the so-called spinal irritation (to be described in the second part of this work), that such an action of blisters proves useful. Another action of blisters, which some authors hold to be perhaps the most effective portions of their agency, is that which is produced by the drain of fluid, specially when they are kept open, by which means a kind of depletion is set up, and the morbid irritation that causes the nerve pain removed. I cannot at all assent to this view. In the first place, I believe that any one who has large experience of blistering in neuralgia will ultimately come, as Valleix did, to believe that prolonged drain from a blister is rarely or never useful, and that a far better plan is that of so-called flying blisters, renewed at intervals if necessary. The most genuine successes that I have procured from blistering have certainly been got in this way. But I should go further, and say that the prolonged drain and the peculiar kind of chronic irritation produced by a suppurating blistered surface can very decidedly aggravate a neuralgia; this is more especially the case when the blister is applied immediately over the focus pain.