Another question to be decided is, how far the treatment is to be influenced by any existing complication of the intermittent fever. Some have supposed that a coexisting inflammation contraindicates the use of quinia, and that the inflammation should be subdued before commencing with the administration of that medicine. I have long been of a contrary opinion. If the inflammation is insufficient to sustain a febrile excitement between the paroxysms, that is, to convert the intermittent into a remittent, it is either periodical itself, and obeys the laws of periodical diseases in general, or is insufficient to be materially aggravated by the stimulant properties of sulphate of quinia. Indeed, the general stimulation of the paroxysm is vastly greater than that of the medicine, and consequently much more likely to aggravate the inflammation. It would seem clear, therefore, that by interrupting the paroxysms we must, instead of aggravating, really relieve the inflammation, by removing the most powerful source of excitement. If theory justifies the use of the antiperiodic under these circumstances, experience is no less decidedly in its favour. I have never known the inflammation, attendant on a perfect intermittent, to be increased by the use of quinia; I have not known it to prevent the antiperiodic medicine from having its due effect; while I have observed that the inflammation is mitigated, and indeed often ceases, almost immediately upon the interruption of the paroxysms; and I believe that my experience, upon these points, coincides with that of the great majority of practitioners in the miasmatic districts of the United Suites. 1 am, indeed, prepared to go further, and to state that the same thing is true, in a great degree, even when the inflammation is sufficient to maintain some fever between the paroxysms; but, in such cases, I should premise blood-letting, general or topical, or both, when apparently called for by the severity of the local disease, and permitted by the state of the pulse. The same reasoning applies here as in the former case; the stimulation of the paroxysm is vastly greater than that of the medicine; and experience equally confirms its justness by the result. There are only two instances, in which I would admit of an exception to the general rule; namely, when the cerebral centres, which are especially susceptible to the stimulant influence of quinia, and the mucous membrane of the stomach, which is liable to be irritated by it, are the seat of the inflammation; and, in the latter case, though I might not administer the medicine by the stomach, I should not hesitate to give it freely by the rectum or hypodermically. If inflammatory complication offer no contraindication to the use of quinia in intermittent fever, I know of no other impediment, unless it may be active cerebral congestion, which should if possible be removed, prior to its employment.

Much has been said of the proper period for the administration of quinia. Some give it indiscriminately at all periods of the disease, without reference to pyrexia or apyrexia; but the great majority confine its employment to the intermission, and, as I think, correctly, unless in certain cases of pernicious fever, where it is of the utmost importance that the approaching paroxysm should be prevented, and there is reason to apprehend that the intermission may be too short for the purpose. In the first place, there is no necessity for giving the quinia during the paroxysm; and, secondly, though it may often be given with impunity, yet there is always some risk of aggravating into positive inflammation any pre-existing tendency to it in the brain or the stomach, or of causing effusion of blood in cases of active cerebral congestion. In the true pernicious variety, in which the great danger arises from defective or perverted innervation of the vital organs, and there is little tendency to active congestion or inflammation, the risk from quinia in the paroxysm can scarcely be said to exist, while the loss of time in withholding it may be fatal. There is one caution, however, which should be observed in the use of quinia during the pernicious paroxysm; namely, never to give it so largely, in the cold stage, as to induce its secondary sedative effect, and thus add to the prostration, which is often itself very alarming, and not unfrequently fatal. Admitting then that, as a general rule, the medicine should be given only in the intermission, we have still to determine at what time, during this period, we are to begin with it, and when to suspend it. Without referring particularly to the various shades of opinion among authors on this point, I will merely state my own, based upon what is known of the action of quinia, and upon personal observation, that the best plan is to commence immediately after the cessation of the paroxysm, and to continue, with repeated doses, until within about an hour of its expected recurrence, so that, at the time referred to, the system may be under the full influence of the medicine.

I prefer the exhibition of the sulphate of quinia in small doses, repeated at intervals of an hour or two, to the use of the full quantity, required for a single intermission, in one or a very few doses. We thus incur less risk of irritating the stomach, or over-exciting the brain, while we have it in our power to modify the dose, if the effects should be unexpectedly and unnecessarily severe. The absorption is probably also more complete, and the whole amount necessary for the required effect diminished. But there are circumstances which justify, and even demand a departure from the general rule; as when the intermission is very short, or when it occurs at night, so that a frequent administration might interrupt sleep, and in this way injure the patient. In such cases, the whole quantity may be given in one, two, or three doses; care being taken to throw the medicine mainly into the earlier period of the apyrexia; as, if withheld until immediately before the paroxysm, time is not allowed for its absorption and full operation, while, even if confined entirely to the earlier period, as its action continues for many hours, this may be in full force at the time required.