ARTIFICIAL HATCHING 129 



tunity to eliminate the infertile eggs, which will never hatch. 

 The machine can be handled better if there are only fertile 

 eggs in it. On the third day one can also pick out the eggs 

 that contain dead germs, which, Lf left in the machine, de- 

 compose and cause an offensive smell. While testing the 

 eggs, the rapidity of evaporation can also be determined by 

 the size of the air cell; the larger the air cell, the more rapid 

 the evaporation. Never turn the hatching eggs at testing 

 time, for the process of testing moves and cools them suffi- 

 ciently. A simple homemade tester can be fashioned from 

 a wooden box, eight inches wide by eighteen inches long, and 

 lined with asbestos. The lid can be hinged on, and a door 

 made to latch. Place an ordinary kerosene lamp in the box 

 and set the box up on one end. Cut a hole in one side, exactly 

 on a level with the flames of the lamp. The hole should be 

 a little less in diameter than the transverse diameter of the 

 egg. When testing the egg, pass each one in succession 

 before this opening, holding it close to the opening so that 

 no light will escape anywhere except through the egg. (For 

 a description of fertile and infertile eggs and dead germs, 

 see Chapter X.) 



Hatching Records. — A record should bekeptof every hatch. 

 This can be of simple form, but should show the number of 

 eggs put in, the breed and the date. It should also record 

 the temperature, taken twice daily, the number of infertile 

 eggs tested out, of dead germs found, and the number of 

 vigorous chicks hatched. From this record can be figured 

 the percentage of the hatch and this data is valuable for 

 future hatching seasons. 



Care at Hatching Time. — About the nineteenth or twen- 

 tieth day the attendant should be on the look-out for signs 

 of pipping, and when he notices the first cracked egg, he 

 should sprinkle them all with luke-warm water. The machine 

 should be immediately closed and kept closed until the 

 hatch is over. During this time the temperature must be 



