INCUBATION OF THE EGG OF THE COMMON FOWL. 363 



results indicated that eggs placed obliquely hatched a far higher 

 percentage than those placed flat. 



In a second experiment, the eggs were arranged in precisely 

 the same manner, but in another incubator provided with a 

 special ventilating apparatus. The fifth day, the eggs placed 

 obliquely were tested and eight discarded. On the ninth day, 

 three dead embryos were removed, and on the sixteenth day, 

 four more were dead, leaving a total of fifty-three living eggs ; 

 forty-seven chicks hatched. Of the remaining six, four were 

 dead in the shell, and two pipped. Thus there were hatched 

 from those eggs placed obliquely, 88.7 per cent, of the fertile 



eggs. 



From the forty-eight eggs placed flat, seven were found infer- 

 tile on the fifth day. On the ninth day, six dead embryos were 

 removed. On the sixteenth day, but one dead embryo was 

 found. Thirty four chicks hatched. There was hatched about 

 83 per cent, of the fertile eggs. 



The results of the foregoing observations and experiments 

 taken together, lead to the deduction that when the supply of 

 fresh air (oxygen) is inadequate, the oblique position of the egg, 

 thereby bringing the embryo in closer contact with the air cham- 

 ber, is decidedly advantageous. When there is an abundant sup- 

 ply of fresh air, there is but little to be gained through placing 

 the eggs obliquely. 



TURNING OF EGGS. 



How many times the hen turns her eggs during the time of 

 natural incubation is a question often asked, but as yet unan- 

 swered. Reaumer ('49, p. 166) states that they are turned daily 

 and Dareste ('91, p. 161) that they are often turned twice daily. 

 Believing this to be a point well worthy of investigation, a series 

 of observations was made with the hope of obtaining some in- 

 formation as to the influence this factor plays in development. 



Experiments have previously been made with a view of ascer- 

 taining what influence turning the egg has upon development. 

 Dareste ('91, p. 165) placed sixteen eggs under the same condi- 

 tions of artificial incubation. Eight were unmoved, while the 

 remaining eight were turned twice each day. In the first set 

 absorption of the yolk did not occur in any case ; the embryos 



