Describe in your own words how evaporation of perspiration control the body.

Sweating is the body's natural response to stress, be that stress hear or stress from a new job interview. The main purpose of perspiration is to cool the body. Losing fluid from specific parts of your body; your chest and armpits to cool you abdomen and preserve your vital organs. Your forehead and neck to cool your brain and throat temperature. As you perspire and it evaporates it keeps the skin from drying out and the organs from overheating. It is a natural body thermostat that Humans couldn't survive without. 

Blood transfusions were rarely done and often fatal; they were outlawed until the nineteenth century.