SIXTY-FIVE FIGURESA t the time that dietltylstilbestrol was heiiig administered to adult rioriiial aiid castratecl male Triturus viridescens (Adams, '46), a similar. series of clipcrinierits was ruit 011 normal aiid castratecl adult females in order t o cleteriiiine wliat effect this syntlietic co~iipo~iiid, knowii to have estrogenic properties (Dodds et al., '38), mo1dd have on the sex that iiorrnallp produces estrogens. As in the experiincrit 011 males and in another one with testosterone propionate (Adams, Gay and Terzian, '41) sesame oil3 was used as the solvent.It was fouiid that prolonged administration of cliethylstilbcstrol produced a iiiarkecl effect o n the ovaries of the nomial females. The average ovarian weights in newts injected weekly with stillnestrol up t o 91 days (series I to 1IJ) were liiglier tltaii those in (1) "beginning controlP," (2) "end ~01itr0ls" (except f o r series I) arid (3) SO-injected contm1sBrief reports embodying some of these icsiilts Twrr piinted in the abstracts of thr Americ;cn Society of Zoologists for 1946 (Annt. Rec., 96: 57.5) and of the Amcricaii Association o f 4uatomists f o r 1947 (Anat. Rec., 9 7 : 410).