LXXV. I am confirmed in the truth of the remark I have just made, by the reflexion, that a diversity of appetites, must undoubtedly proceed from a diversity or alteration of temperaments; and it follows of course, that every alteration in the temperament, must be attended with an alteration of the appetite. It is easy to discern, that no sick person, preserves his appetite in the same even state, in which it continues when he is in health; and this not only with respect to the quantity he eats and drinks; but with respect to the quality of his nourishment also; nor is this confined to the objects of his palate only, but extends to those of all his other feelings and inclinations, both internal and external. SECT. XVI. LXXVI. The second capital error committed in making experimental observations, and which is more common than the first, is that of mistaking for the cause, something that intervenes by accident, and is neither cause nor effect. There is scarce any sick person, who does not fancy he knows what has been the cause of his disorder, which he generally imputes to something particular that he has done, or some alteration he has made in his way of living a little before he was seized with his distemper; although the thing to which he imputes it, bears no allusion to, nor any proportion with the disorder that afflicts him. The having eaten an olive more than it was usual for him to eat, or having fasted a quarter of an hour longer than his usual time, or having drunk two spoonfulls more than common, or abated twenty yards of his ordinary walking, together with some other particulars, that are equally trifling and insignificant with those we have mentioned; but notwithstanding the futility of these observations, he is apt to impute to such causes the disorder he labours under, without reflecting, that this machine of ours, from the weakness of its own texture, is sufficiently exposed to its breaks, ebbings and flowings. The humours of the body, even when the influence of all external causes, and every thing that depends on our own free will, are regulated with perfect uniformity, are nevertheless exposed to various alterations. The heterogeneous nature of them as they respect one another, and also considered with respect to every particle of each of them separately, must necessarily conduce to their being in different states. If those superstitious spirits, who are such idolaters of their health, that with respect to their own regimen they would weigh even atoms, would well consider this, they would free themselves from the continual anxiety in which they live, and which is more pernicious to them, than those very indispositions they are so terrified at, and which they are at so much pains to escape.