HITING (1945), working on the parasitic wasp Habrobracon, developed a timing method that distinguished oocytes irradiated in the first meiotic metaphase (metaphase I) from those irradiated in the first meiotic prophase (prophase I) . She used embryo lethality of X-irradiated eggs from diploid virgins, which measured mostly dominant lethality, and found that metaphase I oocytes are approximately...

S long ago as 1921 HOLTHUSEN observed an effect of anoxia on X-rayed A cells. Interest in this factor and its relation to radiation damage has recently been revived. BACQ (1951) has reviewed the earlier work and latest developments have been described by HOLLAENDER, BAKER and ANDERSON (1951), HOLLAENDER (1952) and GILES (1952). One group of investigators has been concerned with the question as ...