into semen." Blood in women is then naturally used to explain the menses. Therefore, when a male and female copulate and semen is emitted in the woman, the menses and the semen mix and begin a process that creates a new organism. "That it is the heat of the semen that gives it the power to concoct the menses is shown, according to Aristotle by the fact that in some insects which do not produce semen the female inserts a part of her body into the male which then is acted upon by the heat of the male". See also Homeostasis On Breath Pneuma (ancient medicine) Thermoregulation References History of biology History of medicine Angiology