(_a_) Opium and the remedies that resemble it are, for the treatment of neuralgia, fully represented by the hypodermic use of morphia, which is the only kind of opiate treatment that ought ever to be employed, save in very exceptional instances. The great reasons for the preference of the subcutaneous administration over the gastric are, the economy of the drug which it affects and the much smaller degree of disturbance of digestion which it causes. The hypodermic injection of morphia, if conducted on correct principles, enables us, when necessary, to repeat the dose a great number of times with but little loss of the effect, and consequently with a much smaller rate of progressive increase of the quantity required; and the absence of depressive action on digestion enables us to carry out simultaneously that plan of generous nutrition which has already been shown to be so important a part of treatment. Indeed, the case is hardly expressed with sufficient strength, when we say that hypodermic morphia is usually harmless to the digestive functions; for in a great number of instances it will be found actually to give an important stimulus both to appetite and digestion; and the patient, who without its aid could hardly be persuaded to take food at all, will not unfrequently eat a hearty meal within half an hour after the injection. The remarkable effects of hypodermic morphia have, however, caused it to be rashly and indiscriminately used, and so much harm has been done in this way that it is necessary to be exceedingly careful in the rules which we lay down for its employment. Upon these grounds I must hope to be excused if, in order to render this work complete, I repeat a good deal of what I have already said in other places. In the first place, I shall speak of the mode of administration, and then of the dose.