THE BREEDING OF CHICKENS 91 



yolked egg is found ii])on being opened to contain another 

 egg in every way normal, instead of tlie expected two yollvs. 

 For some reason, after the egg is completed and is ready for 

 laying, the constrictions that usually take place behind 

 it, forcing it toward exclusion, become reversed and take 

 place in front of the egg, forcing it back into the albumin 

 secreting portion again. This causes a new secretion of 

 albumin which surrounds the shell, and, normal action 

 restored, the egg again travels down the oviduct, is sur- 

 rounded by a second pair of membranes and another 

 shell. 



The so-called "liver spots" or "blood spots" in eggs are 

 due to the rupture of bloodvessels in the follicle or walls 

 oF the oviduct or by the sloughing off of tiny pieces of mem- 

 brane. The clot simply becomes surrounded along with the 

 \i)lk. 'i'lie membrane is usually suspended in the albumen. 



Further Functions of the Sex Glands.— Tlie ])rimary function 

 of the sex glands (o^'ary and testis) is the production of ova 

 and s])i'rniatozoa. They have howe\'er, certain Aery inijjort- 

 ant secondary functions. The remo\al of the testes from the 

 male known as caponizing, w hich has been i)racticed connner- 

 cially for centuries, increases the size of the bird by growth 

 and the laying on of fat, and causes the flesh to remain tender 

 as in a young bird, largely through the failure to de\elo]) as 

 much connecti\e tissue as is normal in a mature male. The 

 neck, saddle, and tail feathers usuall}' grow noticeably 

 longer than in the normal male. The comb and wattles fail 

 to develop, remaining in an infantile condition. 



By way of summary, it may be said that the presence of the 

 testes limits body size, the laying on of fat and feather 

 length, while stimulating the development of the comb. 

 While the body size and the feather develojjnient in some 

 sections of the male are greater than in the female, they are 

 not so great as in the castrated male. 



Goodale' has shown in a careful series of in\estigations 

 that the difl'erence in the length and sluqje of iiluniage 

 between the male and female is largely due to the influence 



' Carnegie Institute of Washiugton, Pub. 24.3. 



