THE EFFECT OF X-RAYS ON BACTERIA

(1) X-rays act like sterilizing agents upon cultures of B.coli and Erythrobacillus prodigiosus, in that the curves are characteristic sterilization or death-rate curves showing that the total counts decrease logarithmically with time. (2) In this experiment B.coli did not show variation or mutation when it was treated with X-rays. (3) With increasing irradiation Erythrobacillus prodigiosus showed a tendency toward lack of ability to produce its characteristic red pigment. By allowing the organism to grow on the plate for a period of five days the greater portion of the colonies produced their pigment. If a transfer of a white colony is made to an agar slant the characteristic pigment is produced in twelve hours. In only one case was it necessary to make a second transfer in order to bring about the development of the pigment. The above is another example of the variation tendency of Erythrobacillus prodigiosus.     

Particle Formation during Water-Vapor Photolysis

Micrometer-sized particles have been produced by the photolysis of water vapor at wavelengths between 1500 and 1700 angstroms. Although the composition of the particles was not determined, the rate of particle production is consistent with the efficient conversion of water photolysis products to particulate matter. Such a process may be of importance in planetary atmospheres.