a cordial reply, Anatomicarum Gabrielis Fallopii observationum examen, generally referred to as the Examen. In this work he recognizes in Fallopio a true equal in the science of dissection he had done so much to create. Vesalius' reply to Fallopio was published in May 1564, a month after Vesalius' death on the Greek island of Zante (now called Zakynthos). Scientific findings Skeletal system Vesalius believed the skeletal system to be the framework of the human body. It was in this opening chapter or book of De fabrica that Vesalius made several of his strongest claims against Galen's theories and writings which he had put in his anatomy books. In his extensive study of the skull, Vesalius claimed that the mandible consisted of one bone, whereas Galen had thought it to be two separate bones. He accurately described the vestibule in the interior of the temporal bone of the skull. In Galen's observation of the ape, he had discovered that their sternum consisted of seven parts which he assumed also held true for humans. Vesalius discovered that the human sternum consisted of only three parts. He also disproved the common belief that men had one rib fewer than women and noted that the fibula and tibia bones of the leg were indeed larger than the humerus bone of the arm, unlike Galen's original findings. Muscular system Vesalius' most impressive contribution to the study of the muscular system may be the illustrations that accompany the text in De fabrica, which would become known as the "muscle men". He describes the source and position of each muscle of the body and provides information on their respective operation. Vascular and circulatory systems Vesalius' work on the vascular and circulatory systems was his greatest contribution to modern medicine. In his dissections of the heart, Vesalius became convinced that Galen's claims of a porous interventricular septum were false. This fact was previously described by Michael Servetus, a fellow of Vesalius, but never reached the public, for it was written down in the "Manuscript of Paris", in 1546, and published later in his Christianismi Restitutio (1553), a book regarded as heretical by the Inquisition. Only three copies survived, but these remained hidden for decades, the rest having been burned shortly after publication. In the second edition Vesalius published that the septum was indeed waterproof, discovering (and naming), the mitral valve to explain the blood flow. Vesalius believed