Figure 8 denotes the appearance of the egg during the eighth day of incubation. If portions of the shell are carefully removed at this stage, the rudimentary intestines may be plainly seen, together with the gradual development of the beak and eyes, as well as the trembling of the pulsating arteries through the whole embryo. [Illustration: FIGURE 8.--EGG AFTER 192 HOURS.] At this stage the operator should mark all doubtful eggs and return them to the machine, as he will find plenty of room there. He will soon become expert, and can detect life and death in the germ at a glance. Experience alone will give the operator an insight into this business. The incipient stages of decay, though easily detected by the expert, cannot be intelligently described by him. The application of a little heat for the short space of twenty days to an inert mass, developing it into active, intelligent life, is simply wonderful. The process and effect he can easily describe, but the procreative power behind it all is beyond his ken. Should a little duckling be taken from the shell on the thirteenth or fourteenth day it will resemble Figure 9. It will kick and struggle several moments after its removal. The yolk is not yet absorbed, but the process is just beginning and will continue until the twenty-fourth day, when it will be nearly absorbed. The egg, from the fourteenth day rapidly assumes a darker hue. [Illustration: FIGURE 9.] The extremities of the little bird gradually develop, the feathers grow, and at the twentieth day the egg is opaque. At this stage the embryo will endure greater extremes of heat or cold than at the earlier stage of the hatch. I should not advise the operator to presume upon this, however, but just make the conditions as favorable as he can, so that the little bird will have the strength to free himself from the shell. I need not say that this is the most critical time during the whole process, and matters should be made as favorable for the little duckling as possible. About the twenty-fourth day he will be already to break the shell, but, unlike the chick, who will make his way out of the shell a few hours after he has pipped, the duckling will lay for forty-eight hours before he is ready to come out. At this time there should be plenty of moisture in the egg-chamber, for should the orifice or broken parts become dry, and the little duckling, in consequence, be attached to the inside lining so that he cannot turn, he can never get out without help. [Illustration: FIGURE 10.]