LXIX. The want of this reflection, occasions great errors to be committed in physic, for by running counter to the course of nature, you must unavoidably mistake the road that leads to the cure. The consequence of mistaking the effect for the cause, is administering as a medicine, what in reality is poison; for it is clear, that if the physician apprehends the humidity and coldness of the water to be the cause of the distemper, when in truth it was produced by the acrid, salt, peccant, or inflammatory humour, I say if this should happen to be the case, and he calculates his prescriptions to correct the humidity and coldness, he by so doing, will inflame and increase the original disorder. LXX. This species of error, is not confined to the case we have instanced, but is capable of being extended to a vast expanse. I am much inclined to think, that all the extraordinary and vehement emotions, both of the irascible, and libidinous kind, which precede distempers a small distance of time before they make their appearance, and for which you can assign no special external cause, are the effects of those distempers, in their original stages; I mean, that in the first agitations of such cases as we are speaking of, a person is apt to fall into violent passions upon very slight provocations, such as he knows by his own experience, were never used to agitate or have that effect on him, and either immediately, or within a few hours afterwards, he is seized with a fever. People are apt to suppose, that the passion was the cause of the disease; but I say, that the disease occasioned the anger; for if this man, agreeable to his natural disposition, was never subject to such violent starts of passion, upon such, or even greater provocations, it necessarily follows, that that which he experienced upon this occasion, must have been the effect of some preternatural internal cause, which lay concealed within him, most probably the first fermentative movements of the peccant humour, which soon afterwards produced a fever. In reality, it is easy for any one to perceive, and I have remarked it many times both with respect to myself and others, that the irascible passion, is much more apt to be inflamed upon slight occasions, in those first stages, or almost insensible beginnings of such indispositions as tend to be somewhat serious, than at other times.