“…Since the work of Voegtlin and Chalkley (1930), Hammett (1929), Rapkine (1937) and others, there have been many studies in which a specific role for sulfhydryl groups has been implicated in the cellular division process (see reviews by Nickerson, 1948, Scherr andWeaver, 1953). There can be little doubt but that the different investigators have studied more than one reaction since sulfhydryl substances are involved in a multiplicity of cellular reactions.…”