The effect of various concentrations of nitrous oxide on the 24-hour explanted chick embryo.

The effects of nitrous oxide on the early explanted chick embryo were investigated using the technique of New (1955). After 22 hours incubation the embryos were explanted and exposed for a further 24 hours to the following gases: air, nitrous oxide (25 per cent), nitrous oxide (60 per cent), nitrous oxide (79 per cent). The oxygen concentration was maintained at normal levels (20.9 per cent) and the balance of the pses was nitrogen. In a fifth trial a 60 per cent nitrous oxide 40 per cent oxygen mixture was used. After exposure the embryos were examined under the dissecting microscope and in histological sections. These revealed no effect on the chick embryo after treatment with nitrous oxide for 24 hours.