The Influence of Gravity and Air-Hunger on Hatchability

Sanctuary, (1925), Hutt (1929), Smith (1930), Hale (1930), and Byerly (1930), have reported and discussed data on malposition in the chick embryo, but no experimental work on the cause of malposition has come to the author’s attention. The present paper is presented as a contribution to the solution of the causes of malposition and to our knowledge of its importance as a factor in hatchability. During the earlier portion of the incubation period the embryo floats freely on the upper surface of the yolk. As incubation proceeds, the embryo turns to a new position relative to the overlying shell whenever the egg is turned. If the egg stands on end, this statement must be somewhat qualified because the ehalazae prevent the embryo from reaching the middle of the upper yolksurface. Since the position of the embryo in the egg is at first determined by gravity, it is reasonable to suppose . . .