When left to itself, the process of fermentation in most of these sugary or starchy liquids will come to a standstill after a while, because the alcohol, when it reaches a certain strength in the liquid, is, like all other toxins, or poisons produced by germs, a poison also to the germ that produces it.

The yeast-bacteria probably produce alcohol as a poison to kill off other germs which compete with them for their share of the sugar or starch.

So even the origin of this curious drug-food shows its harmful character.

We should hardly pick out the poison produced by one germ to kill another germ as likely to make a useful and wholesome food.
[Illustration: PROPORTION OF ALCOHOL IN LIGHT WINE IN BEER IN WHISKEY The liquid shows what part of a tumblerful of each is alcohol.] If man had been content to leave this fermentation process to nature, it is probable that many of the worst effects of alcohol would never have been heard of.

But these lighter forms of alcoholic drinks did not satisfy the unnatural cravings which they had themselves created.