Blisters in the area pellucida, area opaca, and segmental plate of avian embryos

This is a special communication in an area of special interest to all researchers using avian material. Avian embryos in the Northeast, representing four species (chicken, quail, duck, guinea hen), have been found to be drastically deficient in presomitic tissue (segmental plate tissue) between 45 and 60 h of incubation. These deficiencies first appear in the embryo as blisters, then, through tissue repair, they disappear and the embryos continue seemingly normal development. Similar blisters and excrescences appear in the area pellucida and area opaca between 20 and 30 h of incubation. Associated with these blisters and excrescences in very young embryos and blisters in segmental plates, but not necessarily the result of them, is a high incidence of congenital malformation during later development. These anomalies may be affecting the results obtained in avian research.