Diseases of the Reproductive Organs 253 



psuedo-hermaphroditism in fowls. In such cases a true, 

 functioning ovary never develops. There may be a body 

 which in gross features resembles an ovary, but it is inactive 

 and does not take even the first steps in oogenesis (egg 

 formation) . 



There may or may not be a testis like body present in 

 these cases. Not only is the egg producing activity absent 

 in such cases, but also in many of them at least, the internal 

 secretion normally produced by the ovary is lacking also. 

 The bird th^n takes on some or all of the secondary sexual 

 characters of the male. The appearance of such a bird is 

 shown in Fig. 56. 



As "black atrophy" of the ovary is here designated the 

 peculiar diseases of the ovary first observed more than a 

 century ago in England as occurring in pheasants. The 

 striking feature of the disease is that under its influence the 

 bird assumes the plumage appropriate to the male. The 

 change in the ovary and oviduct induced by the disease 

 appears to be an atrophy accompanied by a blackening which 

 is probably a true melanosis. The following account of an 

 outbreak of this disease about fifty years ago by Hamilton ^ 

 is of interest. "In the years 1858, 1859, and 1860 this 

 peculiar alteration of structure in the female organs of 

 generation in the Pheasants was particularly prevalent in 

 some parts of England. I had the opportunity of examin- 

 ing many specimens, and was able completely to confirm 

 Mr. Yarrell's views on this subject. Indeed, the majority 

 of the birds were young females, many of them being birds 

 of the year, some being in their first molt. I found also 

 that the plumage varied and approached that of the male, 

 not in accordance with the age of the bird, but with the 



1 Hamilton, E., "On the Assumption of the Male Plumage by the 

 Female of the Common Pheasant." Proc. Zool. Soe., London, 1862, 

 pp. 23-25. 



