This section is from the book "A Treatise On Therapeutics, And Pharmacology Or Materia Medica Vol1", by George B. Wood. Also available from Amazon: Part 1 and Part 2.
Our attention is next to be directed to the effects of camphor on the system at large. Omitting the impression it may produce on the stomach, which will vary with the predominance of the refrigerant influence of the evaporation, or the direct excitant influence of the camphor, and with the mode of its exhibition, whether in solution, finely divided, or in mass, I shall notice only the constitutional effects. From a very small dose, sufficient, however, to make a decided impression in certain morbid states of the system, no sensible effect whatever is experienced in health. A somewhat larger dose will usually be followed by a slight increase in the frequency and perhaps fulness of the pulse, and in the warmth of the surface, and occasionally by some diaphoresis. In the course of about twenty minutes, there may be a slight exhilaration of spirits, or feeling of comfort induced, which, however, is much more observable in depression or uneasiness from nervous disorder than in health. This passes over in a short time, and no other discoverable effect may be produced. Thus far the medicine operates in exact accordance with the class of nervous stimulants. A larger dose will occasion obvious narcotic symptoms. With or without preliminary excitement of the circulation, there will now be a feeling of giddiness, perhaps also of languor or lassitude, with more or less mental confusion or unsteadiness; and, if the impression be very decided, there may also be some disorder in vision and hearing. These symptoms are soon followed by heaviness, mental hebetude, and a disposition to sleep; during which the general sensibility is impaired, the pulse, whether at first excited or not, usually becomes slower, though perhaps still full, and the temperature of the surface is somewhat lowered.
Very opposite statements have been made, in reference to the effects of the medicine upon the urinary and genital organs, by persons who equally speak from their own experience, and, so far as can be determined, are equally deserving of confidence. While, according to one statement, camphor is apt to irritate the urinary passages and the organs of generation, producing even strangury in the one, and sensations of voluptuous excitement in reference to the other, the opposite statement affirms that the medicine, instead of causing, is admirably adapted to relieve strangury, and is a powerful antaphrodisiac, producing excellent effects in priapism, nymphomania, a disposition to onanism, etc. Now these assertions are not so contradictory as they seem. Allowing the camphor to act upon the nervous centres as a stimulant, the first stage of its action may be an excitation of the function over which the centres respectively preside, while, in the second stage, the congestion of the centre shall be such as to impair its power, and consequently depress the dependent function. Thus, camphor may excite, and may depress the generative organs, and whether it will do the one or the other, may depend upon the stage of its action, as well as on the quantity given, and on various circumstances which may hasten or retard, increase or diminish its influence. If it act promptly and powerfully on the centre, the first stage of excitation may pass over so rapidly that only the succeeding sedative effect may be felt; if, on the contrary, less rapidly and less powerfully, its congestive effect in the centre may not pass the boundary of pure excitation, and the function be stimulated accordingly. The different effects on the urinary passages may be explained on the same principles; or we may suppose that, in producing one effect, the camphor may act through the system, and, in producing the other, locally.