212 A YEAR IN AGRICULTURE 



Pupils should copy this table in their notebooks and fill in 

 the information gained. 



(b) Practice in examining 1 eggs for freshness. Provide 

 a large shoe-box and a lamp or other light for this exercise. 

 Place the light in the box and hold the egg between the light 

 and a small hole made in the side of the box through which 

 the observer may examine the egg. If no cloudiness is seen 

 in the egg it is fresh. Examine a number of eggs by this 

 method. 



(c) Let each pupil break open an egg in a saucer and 

 note the following points in its structure: The germinal 

 disc, which appears as a light colored spot on the upper 

 surface of the egg and contains the life principle of the yolk. 

 It should be noted here that the egg with its white and yolk 

 is a single cell ; the egg of the ostrich being the largest single 

 cell in animal or plant life. Note the whitish cords of denser 

 albumin which serve to keep the yolk properly suspended in 

 the white of the egg. Note the clear watery appearance of 

 the white of the egg. This is albumin, the food in liquid 

 form upon which the young chick lives while in the shell. 

 The chemical composition of the egg is as follows : Shell, 

 10.7%; albumin, 11.9%; fats, 12.8%; salt, 7%; water, 

 63.9%. 



(d) For this part of the study each pupil should have a 

 hard boiled egg. Carefully remove the shell, piece by piece. 

 Observe the air space and the two membranes beneath the 

 shell. Cut the egg lengthwise through the middle. Make a 

 drawing of the section, showing all the points mentioned 

 under (c). 



5. Preservation of eggs. Eefer to the paragraph in the 

 chapter describing the method of preserving eggs by means 

 of water-glass. As a practical exercise in this study, the 



