Lemons like most citrus are preserved in natural acid that is absorbed through the stomach and then to the blood stream where they cleanse the veins and then exhaled leaving their alkaline minerals behind. This only happens on an empty stomach of course.
In France a famous healer used lemons like this;
1 lemon if you don't feel right.
3 lemons if your ill.
5 lemons if you have a disease.
10 lemons if you awake and believe you will die this day.
You can also use lemons to restore meat to the bones, etc. and many things. This is why you should read books that instruct about Nature.