Effect of Multiple Turning upon Growth of Chick Embryos

THE influence of turning upon hatchability of eggs has been extensively studied, but the author is not aware of any evidence showing the effect of turning upon embryonic growth. Use is generally made of daily wet weights in studying embryonic growth, but differences in other procedure often make a comparison of investigations difficult. In this connection it is interesting to note that Romanoff (1929) showed that nine investigators obtained approximately the same growth curves when their data were grouped and a graphical comparison was made. While the important physical factors had a direct effect in producing the variability in these data, the lack of closer agreement might be due, in part, to a difference in the number of daily turnings which these investigators used. EXPERIMENTAL The eggs were selected for uniformity in size, shape, and shell texture from a flock of 42 S. C. White Leghorn yearling hens. The two . . .