Abstract
The effect of nitrogen and of carbon monoxide administered as post-radiation treatments has been investigated. The hatchability of Habrobracon eggs treated in first meiotic metaphase was taken as the criterion of damage. Both gases are equally effective in enhancing the damage induced by the radiation. Since restitution is thought to be rare in irradiated metaphase oocytes, the action of these gases is considered as altering a repair mechanism which results in allowing potential damage to become actual.