COMMON PHEASANT. 319 



the females, which is well known to sportsmen and game- 

 keepers, by whom such birds are usually called Mule 

 Pheasants. The name is correct, since some of our diction- 

 aries show that the term mule is derived from a word which 

 signifies barren, and these hen Pheasants are incapable of 

 producing eggs from derangement of the generative organs ; 

 sometimes an original internal defect, sometimes from sub- 

 sequent disease, and sometimes from old age. The illustra- 

 tion given on the next page represents on a small scale a 

 preparation of part of the body of a healthy female Pheasant 

 in winter, in the left hand figure ; and that of a diseased fe- 

 male Pheasant on the right hand. The disorganisation is 

 marked by the appearance of the dark lead colour pervading 

 the ovarium, situated on the middle line, and between the 

 two kidneys, which dark colour is seen in patches on various 

 parts of the oviduct below ; and I have never examined a 

 hen Pheasant assuming the plumage of the male without 

 finding more or less of the appearance here indicated. The 

 subject, however, in its details, is unsuited to this popular 

 work ; but those who desire to carry their investigation 

 further will find a paper by Dr. Butter in the third volume 

 of the Memoirs of the Wernerian Society ; one by John 

 Hunter in the various editions of his Animal (Economy, 

 and one by myself, published in the Transactions of the 

 Royal Society for the year 1827. I have seen this disor- 

 ganisation and its effects among birds in the Gold, Silver, 

 and Common Pheasants, in the Partridge, the Peafowl, the 

 Common Fowl, the Crowned Pigeon, the Kingfisher, and 

 the Common Duck : in the latter species, in two instances, 

 the change went on even to the assumption of the two 

 curled feathers above the tail. Other classes of animals are 

 liable to an influence similar in kind, and the effect is 

 singularly conspicuous among insects and Crustacea. 



