Surgical manipulation of the developing chick embryo in ovo after the 4th day of incubation

Surgical manipulations were performed on the eyes of the developing chick embryo between 6 1/2-12 days of incubation at stages when operations had to be performed through the shell and the extra-embryonic membranes. A sufficient proportion of the embryos survived a postoperative incubation period of 6-10 days to analyse the effects of surgical intervention on development.