ABSTRACT
One of the first students of behavior in Paramecium was H. S. Jennings, who published his studies in a book called the Behavior of the Lower Organisms.1 Jennings described in great detail the normal swimming behavior of Paramecium, including one of the major behavioral responses, the avoiding reaction, in which Paramecium at times would be stimulated, for example, by touching its anterior end on an obstacle in the medium. It then would stop its forward progress, reverse its direction of swimming, and then resume forward progress in a different direction. Other behaviors-thigmotaxis, geotaxis, chemotaxis, thermotaxis, and galavanotaxis-were also noted by Jennings.
