After an egg has been under incubation for thirty six hours, it will, if fertile, when held to the light, show a small dark spot a trifle larger than a pin's head. This little spot is the life germ and shows the egg to be fertile. From this time the development of the germ into the duckling can be plainly seen if the egg be held to a strong light. On the sixth or seventh day the first testing of the eggs should be made and all infertile ones taken out. The germ is very distinct at this time, and there has been a gradual change going on in the interior of the egg. The little spot has been constantly enlarging and becoming more dense, and little veins are seen running in divers directions. This is the appearance of an egg with a strong, live germ, which under favorable circumstances will produce a duck. An egg that is not fertile on the sixth or seventh day will be perfectly clear and transparent; all such should be removed at once, as it is useless to allow them to remain. Another kind of egg often seen is a weak or imperfectly fertilized egg, and shows an irregularly-shaped blood vessel, which had started but lacked vitality enough to continue. Such an egg will not hatch and should also be removed from the nest or incubator. Frequently the germ in an egg will show life when tested on the seventh day, but lacks the vitality to carry it through, and when tested later will show dark, irregular blotches over the surface of the egg. These will not hatch, and should be taken out when noticed. On the fourteenth day the little creature inside the egg begins to assume shape and show considerable life. It has increased many times in size since it was seen on the seventh day; the red veins have become more numerous and have spread over the entire surface, while the yolk is scarcely distinguishable from the other portions. The pupil of the eye has now become distinct, and the projection of the wings is clearly perceived. The absorption of the yolk has also commenced, and this will continue until the twenty-fourth day, when it will be nearly completed. The egg from this time on will rapidly grow opaque, and at the eighteenth or twentieth day is entirely so. On the twenty-fourth day the duckling is ready to make its way out of the shell, and in forty-eight hours after pipping the shell it will be entirely out. NATURAL INCUBATION. Hatching under the sitting hen (generally used for hatching ducks) is what is termed the natural process of incubation. The hatching of eggs by this means has always been followed, and no special skill is needed for success, provided the eggs are well fertilized with healthy germs. Many who raise ducks in large numbers, however, use almost exclusively artificial means; some use both the natural and the artificial, while others use the natural entirely.