But how does impregnation take place in vultures if only females exist? This is fully answered in a passage of Horapollo.[1] At a certain time these birds stop in the midst of their flight, open their vagina and are impregnated by the wind.
Unexpectedly we have now reached a point where we can take something as quite probable which only shortly before we had to reject as absurd. It is quite possible that Leonardo was well acquainted with the scientific fable, according to which the Egyptians represented the idea of mother with the picture of the vulture. He was an omnivorous reader whose interest comprised all spheres of literature and knowledge. In the Codex Atlanticus we find an index of all books which he possessed at a certain time,[2] as well as numerous notices about other books which he borrowed from friends, and according to the excerpts which Fr. Richter[3] compiled from his drawings we can