[A simple lesion-free drop of the chorio-allantoic membrane of the chick embryo (author's transl)].

In the embryonated 4-5 days old chicken egg incubated in the normal vertical position, only the blunt top end, a small part of the egg surface, is covered by the embryo. Soon after rotation of the egg to the reverted vertical position with the blunt end down, the egg shell is pierced and the artificial air space is formed on the pointed end which is far from the region occupied by the embryo. Thus any possibility of lesion is avoided.