An enthusiastic speaker preaching temperance (abstinence from alcoholic liquors) was delivering his popular lecture-demonstration on the ill effects of alcoholism. After emphasizing the ill effects, he came to the demonstration part, and placed two glasses on the table (one containing water, and the other alcohol), and an earthworm in a dish.
He held the earthworm by its tail and submerged it in the glass of water for some time. On pulling it out the worm was wriggling and alive. Next he repeated the act and dipped the worm in the glass with alcohol. On withdrawal from this glass the worm was listless, and appearing to be almost lifeless.
Later, to gauge the impact of the lecture, he threw a question to the audience.
What lesson do you learn from this demonstration?
A quizzical silence descended over the audience, till a person at the back got up and shouted, "Alcohol is good for worm infection".
What followed is anybody’s guess.