In 1690, his first book, "Pharmacopoeus synopticus", appeared. The pharmaceutical textbook had two further editions during his lifetime. In 1693 he returned to Horn, but found no prospects there as a pharmacist. He traveled to Hungary and became a physician of the Venetian Doge and naval commander Francesco Morosini. Barchusen accompanied Morosini on a military expedition to Morea but the 75-year-old Morosini died January 1694 in Nafplion.