Ruth Myrtle Patrick was a pioneering ecologist and taxonomist whose extraordinary career at the Academy of Natural Sciences of Philadelphia spanned over six decades. In 1947, an opportunity arose for Patrick to lead a new kind of river survey for the Pennsylvania Sanitary Water Board to study the effects of pollution on aquatic organisms. Patrick leveraged her already extensive scientific network, which included ecologist G. Evelyn Hutchinson, to overcome resistance within the Academy, establish a new Department of Limnology, and carry (...) out the survey, which was a resounding success and brought much needed money to the Academy. As demand for her expertise grew among industrial companies, such as the chemical company DuPont, Patrick became more active in the world of applied science. She repurposed data and instruments from her river surveys to run new experiments, test ecological theories, and conduct long-term ecological studies. Through these studies, she advanced an argument that biologist Thomas Lovejoy dubbed the “Patrick principle,” the idea that the ecological health of a body of water could be measured by the relative abundance and diversity of species living there. Patrick was elected to the National Academy of Sciences in 1970, became a board member of DuPont in 1975, and received two of the most prestigious awards in ecology: the Eminent Ecologist Award from the Ecological Society of America in 1972 and the Tyler Ecology Award in 1975. This article analyzes Patrick’s unusual success in bridging the worlds of science and industry and her unusual ability to cross, and redefine, the perceived boundary between basic and applied fields in biology. It argues that Patrick’s position at the Academy, an institution of natural history that was both willing and able to accept money from industrial corporations, is key to understanding her success in, and influence on, the field of river ecology. (shrink)