One thus can say that the bodily counterpart for the most important functions of the soul is found in human blood. You probably know that some people suffer from persecution complexes, seeing all sorts of figures that are not there. Particularly in earlier times, such persons were bled — not a bad remedy, really.
You must not believe that all people in the past were as superstitious as is generally assumed today. Blood-letting was not something derived from superstition. People were bled primarily by applying leeches somewhere on the body that drew off blood. The blood thus was less active. Not necessarily in the case of alcoholics, but for other attacks of insanity blood was less active, and the person fared better.