An Actograph for Small Terrestrial Animals

Abstract

An apparatus for automatic registration of the activity of small animals is described. The animals are allowed to move within a petri-dish on an activity-condenser of copper wires. Any movements of an animal cause a change of capacity in the condenser. These changes are amplified and induce a mirror-galvanometer to throw a moving light onto a cylinder lens of a camera with a moving strip of photographic paper. Preliminary expts. with Calliphora erythrocephala show the activity-intensity to be directly proportionate to light-intensity within the light ranges used.