I can easily see that it would be natural, if, for example, the body were suffering from dropsy, for it to experience the dryness of the throat that usually communicates the sensation of thirst to the mind, so that, as a result, its nerves and other parts would be so disposed that it would have something to drink, thus making the disease worse; just as natural as it would be for a perfectly healthy body to be prompted by a similar dryness in the throat to take a drink that would do it good.