A foetus attached by the placenta to the womb

In 1672, physician and anatomist Reinier de Graaf published his De mulierum organis about the female reproductive organs, with prints by Hendrik Bary. 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.