In this paper I will address the question of the origin of the soul and the intellect in human and animal generation, as it appeared in medical debates of the sixteenth and early seventeenth centuries. How did this issue affect the traditional boundary firmly established between human beings and animals? How was the passage of Aristotle’s “Generation of Animals,” 2.3, used in this context? To answer these questions, I will focus on the embryological discussion of three representative figures of diverse geographical, intellectual and confessional backgrounds: Jean Fernel of Paris, Jacob Schegk of Tübingen and Daniel Sennert of Wittenberg.

Contents
1. Introduction
2. Jean Fernel
3. Jacob Schegk
4. Daniel Sennert
5. Conclusion