Figure 3.—Egg at End of 72 Hours.
The discovery and locations of the minute organisms may be interesting to the scientist, but not at all necessary to the operator, who simply wants to be assured of the life and health of the germ. This he can readily determine from the increased size and gradual development of the circle; it, and the contents of the egg, now assume a darker shade. Up to this time I use no moisture, and the contents of the eggs have gradually evaporated and the air-cell proportionately enlarged. This air-cell is slightly enlarged till the tenth day, when no further evaporation should take place. About three days before hatching the rapidly developing duck will gradually diminish the size of the air-cell, leaving himself just room enough to work out.
