NEW METHOD OF INOCULATING INCUBATED EGGS - APPLICATION TO THE ISOLATION OF INFLUENZA-VIRUS

A simple, direct-vision method of inoculating into the allantoic, amniotic or vitelline sacs of hen''s eggs or onto the surface of the chorioallantoic membrane is described. The inoculation can be carried out precisely and without injuring the embryo. The method involves creating an artificial air cavity at the pointed end of an embryonated egg 5-6 days old, i.e., in the region normally occupied by the albumin. The egg is subsequently placed on its side, causing the artificial air cavity to move the equatorial zone. After cutting away the shell directly over the artificial air cavity the embryo and the yolk sac can be seen through the transparent chorioallantoic membrane, and inoculations can be done without unnecessary damage to the embryo or the blood vessels in the membranes. This method is particularly valuable for the isolation of influenza virus strains.