BREEDING * 97 



mentary tract when they are taken in with food through 

 the mouth. They there enter the developing yolks and 

 remain until the yolks are discharged from the ovary, fer- 

 tilized, and laid. If such eggs are incubated and hatched 

 the organisms are very likely to find their way into the 

 alimentary tract of the chick during embryonic life and 

 multiply to such an extent that the chick will have contracted 

 the disease before exclusion from the shell. Such a condition 

 corresponds somewhat to intra-uterine infection in mammals. 

 It might perhaps be properly termed intra-ovarian infection. 

 The point is, however, that while technically the young 

 creature contracts the disease by infection from the mother, 

 practically the disease is transmitted from mother to the 

 food-supply of the potential offspring before laying or even 

 ovulation occurs. These same investigators found that 

 "more than 25 per cent, of the pullets that were artificially 

 infected as chicks became permanent bacillus carriers." 



The same condition might be found in the case of any 

 infectious disease that involves the ovary or oviduct. Thus 

 if a hen with a tubercular oviduct should lay, the likelihood 

 is that chicks hatched from her eggs would be tubercular. 

 This does not often occur, because a bird with a diseased 

 oviduct seldom lays. 



The Male Generative Organs and Caponizing. — ^The essential 

 generative organs of the male bird are the testicle, the tube 

 leading from it to the cloaca, and the small papillse placed 

 near the margin of the cloacal opening and serving as the 

 organ of copulatio'ii. Each of the three organs is paired. 

 The exact location of th^ testicles is of interest in connection 

 with the reproductive apparatus of the male, because of 

 their importance with reference to castrating or caponizing. 

 They are placed on either side of the median line of the body 

 just back of the lungs and below the anterior extremity of 

 the kidneys. They are oval in shape, and at the time most 

 favorable for caponizing are the size of a small pea. Ulti- 

 mately they beconae so large as to inhibit their removal 

 between the ribs. They are reached in caponizing by an 

 incision between the last two ribs. 

 ' The object of castration in chickens is much the same as 

 7 



