Special Problems of Experimenting <i>in ovo</i> on the Early Chick Embryo, and a Solution

Abstract

ABSTRACT A method has been described for experimenting on the early chick embryo. By its use it is possible to make an opening in the vitelline membrane large enough for the easy performance of any major operative procedure. The air space over the blastoderm is not topped up. The egg is incubated on a horizontal ttirntable, rotating around a vertical axis, at about 8 cycles per minute through an angle of about 90°, until the embryo has reached the end of the 3rd day of development. Successful results, using embryos of 4–12 somites, have been achieved in 74 per cent, of 120 major experimental procedures. The rationale of the method has been explained.