In 1672, physician and anatomist Reinier de Graaf published his De mulierum organis about the female reproductive organs. The book contains detailed prints by Hendrik Bary, among them several of the vagina. De Graaf was the first to conclude that a foetus was the product not just of a man’s seed, but also of a woman’s egg. He discovered what he called blisters, which later became known as Graafian follicles.