Laboratory notebooks preserved at the Acadéémie Royale des Sciences in Paris together with printed summary reports of the same work make possible a detailed reconstruction of chemical investigations undertaken by the Parisian academicians in the later 17th century. Denis Dodart set out the program for the investigations, whihc concerned the principles of plants; Claude Bourdelin did most of the experimental work; which, in keeping with proper bureaucratic procedure, Dodart wrote up for publication. The results did not change the course of chemistry. They and the procedures used to obtain them, however, are of great interest for their detail and accuracy; and the system, perseverance, and numeracy of Bourdelin and his assistants will surprise those who think that elaborate bookkeeping in chemistry came in with Lavoisier. The academicians tried to extract plan ““principles,”” which were of interest to druggists as well as to philosophers——by maceration, soaking, and, most potently, heat maintained at various temperatures over extended periods. Some treatments required the best part of a year. The extracts were subjected to systematic tests with standard reagents to provide reliable identificatons. To help evaluate the academicians achievement in creating new knowledge, the article includes a comprehensive survey of relevant parts of Nicolas Lemery's Cours de chymie of 1675.