[Aristotle on the function of blood in the processes of life]

This contribution explains some aspects of the Aristotelian conception of blood. According to Aristotle, blood is an homogeneous part of the body. It is producted in the heart of the warmest animals through the "cooking" of the nourishment, and then it is distributed all over the body, where it has non only the function to nourish the different organs and to induce their growth, but it also passes on the sense-data. Furthermore in the male creatures blood is the starting-point of the production - through a further "cooking" - of semen. On the contrary in the creatures of the female sex, whose body is colder such a tranformation of blood in semen doesn't happen. In the copulation the semen of the male works as bearer of the form and efficient cause, while the female blood acts as matter The outcome of the ag6n that takes place between the two factors determines for its part the sex of the offspring.