106 POULTRY PRODUCTION 



decisive reason is that because of surgical difficulties it is 

 l)ractically impossible to perform tlie operation successfully. 

 It has been successfully accomijlished a comparati\ely few 

 times by trained in\estigators. Remoxing tlie o\-ary in its 

 entirety usually rcsidts in the rupture of a large blootlvessel 

 lying at the l)ase of the main stock, wliich allows sufficient 

 hemorrhage to cause death. If the organ is not removed 

 perfectly clean, it has the power to regenerate from the 

 remaining tissue and so defeat the purpose of the operation. 



Time Elapsing Between Mating and Fertility. — Pearl and 

 Surface' make note of the fact that in "Some experiments 

 carried out by H. J. Odam of the period elapsing between 

 mating and fertility in one case a chick was produced from 

 an egg laid seventy-two hours after mating." 



Waite^ found that where twenty Single Comb White 

 Leghorn pullets were mated, 50 per cent of the eggs laid 

 on the third day (less than fifty-four hours after mating) 

 were fertile and 70 per cent were fertile on the fourth day. 



In mating eighteen Rhode Island Red pullets and one 

 White Plymouth Rock cockerel, he found that the four 

 eggs laid on the seventh day were all fertile. In still another 

 test with these same breeds, eight eggs laid on the eighth 

 day were all fertile. 



In a test with Single Comb White Leghorn hens mated to 

 cockerels, carried out by Townsley and reported by Philips,^ 

 the first fertile egg was gathered twenty-three hours after a 

 single mating. The detailed data are shcnvn in Table XR'. 

 It will be noteil that the eggs were not 100 per cent infertile 

 until the sixteenth day after the mating occurred. 



Judging from ct)mmon experience in addition to the fore- 

 going, it seems safe to state that in practice it will be found 

 that eggs laid by vigorous hens will usually be fairly fertile 

 in six days in the case of Mediterranean breeds, and eight 

 to ten days in the case of the American breetls, winle two 

 weeks is necessary in the case of pullets, assunnng in each 

 case that the male is vigorous and active. 



' Maine Bulletin No. 168. 



2 IVlaryland Bulletin No. 157. 



3 Jour. Am. Assn. Inst, and Invest, in I'oul. Husb., vol. iv, No. 5. 



