This is a group of papers presented at a conference held by the Section of Biology of the New York Academy of Sciences. Groups of workers from several laboratories in this country and in England reported at about the same time the finding of an antibiotic substance from Bacillus polymyxa.
The name "polymyxin" was given to the substance by the American workers, whereas the English group called their substance "aerosporin," having obtained it from Bacillus aerosporus, which some consider the synonym of B. polymyxa. The antibiotic properties reported for these substances were similar, as were the organisms which produced the substances. Materials were exchanged between the laboratories to determine the relation of "polymyxin" to "aerosporin." The papers show that the main active components of "polymyxin" and "aerosporin" are not identical. They are closely related chemically and practically indistinguishable biologically. Other active substances are obtained from B. polymyxa. There is a