Apud Doctorem Ruyschium Amsterodami, 24 May 1693

Notes from a paediatric anatomy demonstration, that appears to have dealt with certain birth defects. Followed by what appears to be a note about an actuarial problem concerning human senescence; several individuals who have worked on it are named, including Christiaan Huygens. Then follows a diagram of a machine designed by Jan Hudde for descrying a curve of changing slope. Last is a note about a conversation with Hudde about calculating dimensions and focal length of lenses in apertures.