Jacob Hiltzheimer, farmer and assemblyman, emigrated from Germany to Philadelphia in 1748 and lead a moderately active political and social life. He was a successful farmer and raised select livestock in the city of Philadelphia. He also boarded horses including those of John Penn and George Washington. He served in the Pennsylvania Assembly for 11 consecutive years beginning in 1786. He was an active contributor in civil affairs and took a remarkable enthusiastic interest in events, in persons, and in every day life all of which he wrote down in his diary. As a result of his Revolutionary War and political acquaintances his contacts were numerous. Hiltzheimer's record of social affairs are for the most part routine daily events such as buying and trading horses, attending barbecues and funerals, and drinking punch. However it is his every day accounts that also records significant events such as the Revolutionary War, transactions of the Pennsylvania Assembly, and Philadelphia's yellow fever epidemics, as well as the dealings of significant people including George Washington, Thomas Mifflin, and John Hancock.

This volume contains medical notes by Wistar, including observations on yellow fever and arguments to prove its foreign origin, facts relative to the progress of the fever in 1797, the infection and death of Colonel Van Emburgh, the infection of the crew of the ship "Deborah" and of the Durham boat (1802), an account of the diseases which afflicted the family of James Hammar in Montgomery County (Pa.), facts relating to the typhus fever of 1812-1813, case histories (1796-1803), temperature chart (1758-1759, 1760), and a thermometrical journal (1760-1765) kept by Charles Norris and copied by Wistar from notes in possession of Joseph Parker Norris.