The Electrical and Mechanical Events of Neuro-Muscular Transmission in the Cockroach, Periplaneta Americana (L.)*

Though the mechanical activity of insect muscle has been studied by many workers (notably Heidermanns, 1931 ; Solf, 1931 ; Kraemer, 1932; Cremer, 1935), and insect-muscle potentials have been recorded by Rijlant (1932) and Pringle (1939), no attempt has been made to examine the precise relation between motor-nerve impulse, muscle potential, and muscle contraction in this group. The purpose of this account is to examine the electrical and mechanical signs of neuro-muscular events in the cockroach, and to evaluate them in the light of current concepts of neuro-muscular transmission in Crustacea and invertebrates.