Second, that even in the smallest doses, as a deadener of the sense of discomfort, it blinds the man who takes it to the harm it is doing and, as soon as its temporary comforting effects begin to pass off, naturally leads its victim to resort to it again in increasing doses. In fact, unlike a true food which quickly satisfies, the use of alcohol too often creates an appetite that grows by what it feeds on, and is never satisfied. For every natural appetite or instinct, nature provides a check; but she provides none for tastes that must be acquired. The last man to find out that he is taking too much is the drinker himself. Taken first to relieve discomfort, its own poisonous after-effects create a new and permanent demand for it. The third point on which agreement is almost unanimous among scientists and physicians is that, as will be seen in later chapters, there are a considerable number of diseases of the liver, of the heart and blood vessels, of the kidneys, and of the nervous system, which are produced by, or almost always associated with, alcohol. There are, for instance, three different kinds of alcoholic insanity. It is true that these disease-changes most commonly occur in the tissues of those who use alcohol to excess; and it is also probably true that what the alcoholic poison is doing in these cases, is picking out the weak spots in the body and the weaker individuals in the community. Even the strongest and best of us have our little weaknesses of digestion, of nerves, and of disposition that we know of, as well as others that we are not acquainted with. And what is the use of running the risk of having these picked out and made worse in this dangerous and unpleasant manner, just for the sake of a little temporary indulgence? Moreover, while it is admitted that most of these harmful effects of alcohol are produced by its use in excess, it is daily becoming a more and more difficult matter to decide just how much is "excess." It certainly differs widely in different individuals, and in different organs and parts in the same body. An amount of alcohol which one man might possibly take without harm may greatly injure another; and its frequent use, though it does not produce the slightest sign of intoxication, or even of discomfort, or headache, may be slowly and fatally damaging the cells of the liver or kidney. In fact, the conviction is growing among scientists that alcohol does the greatest harm in this slow, insidious way without its user's realizing it in any way until too late to break the fearful habit.