Are "Progressive" Mutations Produced by X-Rays?

PAGE 495 1. The physical background of the problem. .................................... 11. Evidence concerning the duality of the X-ray effect on chro 111. A partial separation of the Werent genetic effects of X-rays.. . . . . . . . . . . IV. The production of multiple allelomorphs.. ..... ........................... 507 V. An induced mutation visibly d8erent from a known lass of VI. First attempts to induce mutations in both of two oppqsite VII. Reverse mutations a t the locus of scute. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . VIII. A reverse mutation a t the locus of forked.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . IX. Proof of the induction of reverse mutations of forked