If according the best information from antiquity the vultures were directed to let themselves be impregnated by the wind, why should the same thing not have happened even once in a human female? On account of this use the church fathers were “almost all” in the habit of relating this vulture fable, and now it can hardly remain doubtful that it also became known to Leonardo through so powerful a source.
The origin of Leonardo's vulture phantasy can be conceived in the following manner: While reading in the writings of a church father or in a book on natural science that the vultures are all females and that they know to procreate without the coöperation of a male, a memory emerged in him which became transformed into that phantasy, but which meant to say that he also had been such a vulture child, which had a mother but no father. An echo of pleasure which he experienced at his mother's breast was added to this in the manner as so old impressions alone can manifest themselves. The allusion to the idea of the holy virgin with the child, formed by the authors,