RANKIN'S DUCK BOOK 



same amount of flame in relighting your lamp as it had pre- 

 viously. 



Keep both lamps and chimneys clean, and have stated 

 periods for turning your eggs, which should be done twice 

 each day. As I said before, an egg-tester is not required with 

 duck eggs, as they are so transparent that the whole process 

 can be plainly seen without in the flame of a common kero- 

 sene lamp. If a duck egg is carefully, examined, after being 

 subjected to a heat of 102 degrees for twenty-four hours, a 

 small dark spot will be seen about the size of a large pin- 

 head. This little spot, if the egg is gradually turned, will al- 

 ways float over the upper surface of the egg. This is the life 

 germ, and the first indication of fertility in the egg, and is 

 represented in Figure 1. 



Figure 1. — Showing First Indication of Fertility. 



At the end of forty-eight hours this dark spot will have 

 nearly doubled its size, and a faint haze will appear around 

 its edges a shade darker than the surrounding contents of the 

 egg. This haze is the first appearance of the blood veins rad- 

 iating out from the germ. 



Figure 2 shows how the egg appears at this stage with 

 the air-cell slightly enlarged. 



At the end of the third day the dark spot, which is the 

 heart of the embryo duck, can still be seen ; but not so dis- 

 tinctly, because a dark circle some three-quarters of an inch 

 in diameter will now appear in the upper surface of the egg, 

 in the centre of which the dark spot is visible. This circle is 

 several shades darker than the rest of the egg, and no matter 

 how the egg is turned will always float in its upper surface. 



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