564 DOMESTIC ANIMALS, DAIRYING, ETC. 



held between the eye and a light. In order that the view may be 

 most advantageous, it must be contrasted with a dark border. Many 

 different egg testers have been devised, but they all depend upon the 

 above principle. The simplest in construction is a plain tube about 

 1^ inches in diameter and made of tin, wood, or cardboard. The 

 egg is placed snugly against the opening in this tube, and it is so held 

 that the egg is between the tube and the light and the tube is be- 

 tween the egg and the eye. With the eye close to the uncovered end 

 of the tube, a picture of the egg can be seen through the transparent 

 shell. If the test is made in a dark room, a much better view can 

 be obtained. A very fair test can be made in a dark room by hold- 

 ing the egg before a small aperture in a window shade, provided the 

 sun is shinning against the window. In cloudy weather, when the 

 sun can not be depended upon, some kind of an egg tester is required. 

 All manufacturers furnish some kind of egg tester with every ma- 

 chine sent out, and the most of them work upon the same principle 

 and are operated in the same way. Evening is the best time for 

 making the test. Have ready a low table and an empty tray, also a 

 basin or a basket. The operator can work best if seated at the table 

 with the lamp in front of him ; upon his left is the tray of eggs to be 

 tested, with the empty tray and basin upon his right. Every detail 

 should be arranged before the eggs are removed from the egg cham- 

 'ber, as a prolonged exposure is to be avoided. One by one the eggs 

 are taken from the tray, tested as above suggested, me appearance 

 observed, and the egg, if fertile, placed in the empty tray, or, if in- 

 fertile, placed in the basket. As soon as all are tested the tray con- 

 taining the fertile eggs is replaced in the incubator, the door of which 

 is then closed and the machine left as before. Experience soon 

 teaches one the appearance of the nonfertile and the spoiled egg, as 

 contrasted with that of the fertile egg which has already begun to 

 hatch. The fertile, or hatching, egg will show a spiderlike forma- 

 tion, a center with long crooked threads, or rays, leading outward, 

 and this formation will float as the egg is turned, seeming to have an 

 inherent power of motion. Such eggs are good and the germ is alive 

 and hatching. But if this formation is a black stationary spot and 

 the red lines come together in a circle, the egg is one that has been 

 fertile, but the germ of which is now dead. Such an egg should be 

 removed from the tray at once. The egg that remains clear except 

 for a small dark cloud is infertile and may possibly be used in cook- 

 ing. In case an egg is doubtful it can be marked and returned to the 

 tray and left there a few days to be tested again. All eggs that cool 

 too quickly should be marked for special examination, and remem- 

 ber that the egg that does not contain life will be cooler than the live 

 egg. Cracked eggs can be saved by the use of court plaster, but un- 

 less it be from a rare or valuable fowl the attempt to hatch a broken 

 egg will hardly be worth the trouble. At the second testing, about 

 the tenth day, the eggs that are hatching w r ell will be nearly half 

 darkened, while the others will look more or less as they did in the 

 first test. On the seventeenth day the chick will be seen to fill all the 

 egg but the air space, unless it has died in the shell since the previous 



