This report describes results of continuing experiments directed toward chemical lasers in a flow system and a single-pulse system. A new laminar diffusive-mixing system for obtaining very fast mixing rates is described. Conclusive evidence for lasing action of hydrogen fluoride in the single-pulse system is offered. Certain theoretical considerations are discussed. Fast flow velocities; fast, reproducible mixing; simple flow patterns; and fast, truly homogeneous initiation reaction have been recognized as critical factors in successfully achieving laser action in a continuous-flow hydrogen-fluorine system and several limitations inherent in the initial approach have been removed. (Author).