PROGRESSIVE POULTRY CULTURE 57 



amine closely. The fine net-work of veins should have 

 nearly enclosed the yolk. If there has been a halting 

 and folding at the edges, part of the yolk's surface will 

 be left uncovered by blood-vesels with a consequent fail- 

 ure to utilize some of the sources of nourishment for 

 the growth of the embryo. 



Eight days should have given ample time for the 

 complete surrounding of the yolk by the net-work of 

 veins. An egg should be opened to see how this enclos- 

 ing of the yolk appears at close range. 



Another series of blood-vessels appears the veins 

 of the allantois which starts out at the abdomen of the 

 embryo about the third day of incubation and gradually 

 spreads, with its net-work of large and small veins, until 

 it encloses the white and the yolk together and ramifies 

 over the inner membrane of the soft shell of the egg. 



By the end of the ninth day the large blood-vessels 

 of the allantois show conspicuously, floating in the al- 

 bumen, near the inner shell, in the area just below the 

 air-cell, where also the movements of the embryo are 

 also evident. 



After ten days the allantois veining has become very 

 apparent in the somewhat clear region next to the air- 

 cell. The allantois system of veins helps to darken the 

 shadow before the egg-tester, contrasting strongly with 

 the very clear space shown by the somewhat enlarged 

 air-cell. 



Eleven days of development having taken place, 

 several eggs should be opened in order to observe the 

 embryo, now completely formed as to its body-parts and 

 organs. The little organism will live for some minutes 

 after the egg is opened and the throbbing heart is con- 

 spicuous because of its pulsing as it pumps the blood 

 through the veins that fill the flattened mass of albumen 

 and redden it with their ramifications. 



The next nine or ten days constitute the period of 

 growth of the successfully shaped embryo chick. The 

 rapid increase in size of the body-parts from day to day 

 causes the gradual decided darkening oil the contents 

 of the egg. The numerous blood-vessels help to shade 



