negative electricity is carried off by the earth-wire, and the limb remains charged with free positive electricity. I have had no sufficient experience of this method to give any opinion of its merits, but the inventor thinks it decidedly superior to the ordinary modes of applying the constant current.] (_f_) The last kind of local remedies for neuralgia of which we have to speak are those by which we seek to mitigate the paroxysm by thoroughly excluding the air from the site of apparent pain. These are chiefly of value in those cases where a distinct inflammation (herpetic or erysipelatoid), or an unusual degree of sensitiveness on pressure, etc., has become developed around the superficial branches of the neuralgic nerve. Very much the best agent of this kind with which I am acquainted is the flexible collodion; in neuralgic herpes and erysipelas the effect of this application, conjoined with the hypodermic injection of morphia (preferably in the immediate neighborhood), is of the greatest possible service in mitigating the pain. In herpes it has this further special advantage, that it prevents the occurrence of sores after the vesicles fall, an accident which otherwise will sometimes happen, and which very much increases the severity and intractability of the consecutive neuralgic pain. 4. Lastly, we have to speak of prophylactic measures, which really ought never to be thought of as a separate matter, but always as an essential and most important part of the treatment of neuralgia. The prophylaxis of neuralgia is divisible into (_a_) measures for preventing the development of the neuralgic habit in those who may be supposed to have a predisposition to it; (_b_) measures between the paroxysms; (_c_) measures to be adopted after the attacks have ceased. (_a_) The measures that should be taken to avert neuralgia, in those who may be reasonably assumed to be predisposed to it, have scarcely received any consideration at the hands of systematic writers; yet this is a most important subject. The persons in question are children who belong to families known to be infected with tendencies to neurotic diseases, or persons whose daily occupations submit them to peculiarly strong predisposing influences of an external kind. The hostile influences that should be avoided, or at any rate compensated, are of several kinds: (1) Psychical; (2) defects of nutrition; (3) mismanagement of the muscular system; (4) sexual irregularities; (5) over-fatigue of the special senses, and insufficiency of sleep, especially the latter; (6) unhealthy atmosphere and climate. (1) The psychical influences which must be especially avoided, if we would avert the formation of the neuralgic habit, form a large and somewhat indefinite group, which it is doubtless difficult to deal with satisfactorily. The matter is, however, highly important, and the attempt must be made. And there are, at any rate, some leading principles that I feel justified in laying down with confidence.