The accidents already enumerated are the most common ones which can be considered as depending on the nature of the medicine itself. But, besides these, a variety of others, although less frequently occurring, might likewise be referred to this source. Independent of that affection of the gums and mouth, which, for the most part, is the forerunner of salivation, it sometimes happens, even where no particular exposure to cold can be blamed as a cause, that the whole head is remarkably swelled. Where this takes place, it is in general the consequence of throwing in the mercury too suddenly, and may best be avoided by a more sparing and gradual use of the medicine. From continuing the use of mercury for a considerable time, in some cases, febrile complaints will arise. These, if they admit of a cure, while the use of the mercury is continued, will most readily be overcome by the means commonly employed for the relief of hectic fever. But it seldom happens, that these symptoms can be removed without omitting the use of the mercury. In such cases, therefore, even although from the remaining appearance of a venereal taint, the farther continuance of mercury would seem adviseable, yet, when these febrile symptoms supervene, it is for the most part necessary, to trust the cure to other means. The action of every medicine, and consequently the circumstances claiming attention in its employment, are considerably varied by peculiarities in the habit in which it is given. What, in this respect, therefore, is chiefly to be attended to in the use of mercury, falls next to be considered. Although it has been observed, that the accidents already mentioned may happen in any habit; yet it is certain, that in some particular habits, they will much more readily take place than in others. Where constitutions, therefore, naturally exposed to these accidents do occur, it is necessary, that the means to be employed for preventing the inconveniencies which would arise from thence, should be had recourse to, more early than in patients of a different constitution. Mercury, when introduced into the system, has always a tendency to produce evacuation. At particular periods of life, evacuation is less easily born than at others. Hence, the long continued use of this medicine, or its employment in a considerable quantity, are always particularly to be avoided with people much advanced in life, or with infants. During infancy, mercury may likewise produce inconvenience, from its stimulant power. On this account, the more acrid preparations are, during that period of life, to be avoided. If, however, their use should be esteemed necessary, they are to be employed only in small doses. Stimulants are not more dangerous in irritable habits than they are in plethoric ones; or in those in whom the force of the circulating fluids is very great. On this account, with patients in the vigour of life, evacuation is often requisite previous to the use of mercury.