I 



158 



STERILITY FROM 



Chap. XVIH. 



are completely barren; but this latter case is still involved in some 



obscurity. 



61 



Independently of the 'fact of many animals under confine- 

 ment not coupling, or, if they couple, not producing youno- 

 there is evidence of another kind that their sexual functions 

 are thus disturbed. For many cases have been recorded of the 

 loss by male birds when confined of their characteristic plumage. 

 Thus the common linnet (Linota cannabind) when caged does 

 not acquire the fine crimson colour on its breast, and one of the 

 buntings (Umheriza passerina) loses the black on its head. A 

 Pyrrhula and an Oriolus have been observed to assume the 

 quiet plumage of the hen-bird ; and the Falco albidus returned 

 to the dress of an earlier age. 62 Mr. Thompson, the superin- 

 tendent of the Knowsley menagerie, informed me that he had 

 often observed analogous facts. The horns of a male dee 



the voyage from America were 

 badly developed ; but subsequently in Paris perfect horns were 

 produced. 



When conception takes place under confinement, the young 

 are often born dead, or die soon, or are ill-formed. This 

 frequently occurs in the Zoological Gardens, and, according to 



Eengger, with native animals confined in Paraguay. 



r 



(Cervus Canadensis) during 



The 



mother's milk often fails. We may also attribute to the dis- 

 turbance of the sexual functions the frequent occurrence of 

 that monstrous instinct which leads the mother to devour her 



offsp 



myster 



of 



per 



first 



appear 



dence has now been advanced to prove that 



Sufficient 



aals when first confined are 



eminently liable to 

 their reproductive systems. We feel at first naturally inc 

 attribute the result to loss of health, or at least to loss of 

 but this view can hardly be admitted when we relic 

 healthy, long-lived, and vigorous many animals are unc 



suffe 



how 



61 See an interesting paper by Mr. 

 Newman, in the 'Zoologist,' 1S57, p. 



506 ; Bechstein, ' Stubenvogel,' s. 185 ' 

 ' Philosoph. Transact.,' 1772, p. 271. 



5764; and Dr. Wallace, in * Proc. Bronn (' Geschichte der Natur,' Band ii. 



Entomolog. Soc.,' June 4th, 1860, p. s. 96) has collected a number of cases. 



119. For the case of the deer, see 'Penny 



62 Yarrell's < British Birds,' vol. i. p. Cyclop.,' vol. viii. p. 350. 





