The use of the South African frog (Xenopus laevis) in the study of spinal reflex physiology.

Frogs have been valuable as test animals in neurophysiological and related investigations for many centuries. Basic facts discovered by means of frog preparations include the existence of animal electricity (Galvani, 1791), the anatomical basis of a reflex arc (Hall, 1850), the speed of nerve impulse conduction (Helmholtz, 1850), the inhibition exercised by brain centres on the cord (Sechenov, 1863) and the existence of membrane potentials (Bernstein, 1902). According to Lloyd (1943), the history of contemporary neurophysiology began with the use of the cathode ray oscillograph by Gasser & Erlanger (1922) and the discovery of the compound nature of sciatic nerve action potentials by Erlanger, Bishop & Gasser (1926). In these studies frogs were also employed.