Frederik Ruysch (Dutch: [ˈfreːdərɪk ˈrœys]; March 28, 1638 – February 22, 1731) was a Dutch botanist and anatomist. He is known for developing techniques for preserving anatomical specimens, which he used to create dioramas or scenes incorporating human parts. His anatomical preparations included over 2,000 anatomical, pathological, zoological, and botanical specimens, which were preserved by either drying or embalming. Ruysch is also known for his proof of valves in the lymphatic system, the vomeronasal organ in snakes, and arteria centralis oculi (the central artery of the eye). He was the first to describe the disease that is today known as Hirschsprung's disease, as well as several pathological conditions, including intracranial teratoma, enchondromatosis, and Majewski syndrome.