Coagulation, the response to some broken blood vessel, the conversion of blood from the liquid to a semisolid gel to halt bleeding In general, Greek thinkers thought that blood was created from meals. Plato and Aristotle are two important resources of evidence for this see, but it dates again https://social4geek.com/story5541000/the-smart-trick-of-blood-castle-mu-online-that-nobody-is-discussing