IIEHMAPIIKOD1TISM. 



717 



domestic and wild duck (Anas boseha). 

 Alining the Sc, insmvs it has liren s,.,n in the 

 cuckoo (CuctUui ctmona) by 1'nyr.uideau ; 

 and among llic I'asscres in the cotinga ( Am- 

 ptlis) by Dufresne ; in the chaffinch ( Frin- 

 gillit)'dnd roiifcttjiinn ( Mulncillu) by Prevost ; 

 and in the hunting ( F.mlitriza paradivta and 

 hntgicavda) by Blumenbach. 



This change of plumage in old female birds 

 eommences,acconiing to M.Isidore St. Hilaiiv,* 

 much sooner in some instances than in others; 

 it may only begin to show itself several years 

 after the bird lias ceased to lay, though depend- 

 ing more or less directly upon this phenomenon, 

 and sometimes it commences immediately after 

 it. The change may be effected in a single 

 . though in general it is not complete for 

 some years. When it is perfected, the female 

 may display not only the variety of colours, but 

 also the brilliancy of the male plumage, which 

 it sometimes resembles even in its ornamental 

 appendages, as in the acquisition of spurs, and, 

 in the domestic fowls, of the comb and wattles 

 of the cock. The voice of the bird is also very 

 generally changed. Its female habits and in- 

 stinct are likewise often lost ; and, in some in- 

 stances, it has been seen to assume in a great 

 degree those of the male, and has even been 

 observed to attempt coition with other females 

 of its own species f In most of the female 

 birds that have undergone this change, the 

 ovary has been found entirely or partially dege- 

 nerated, though in a few cases the morbid alte- 

 ration is not very marked, eggs having even 

 been present in the organ in one or two in- 

 stances. In general, however, it is greatly 

 diminished in size, or has become altogether 

 atrophied ; but the perfection of the change in 

 the plumage does not seem to bear any direct 

 ratio with the degree of morbid alteration and 

 atrophy in the ovary. 



That the changes towards the male type, de- 

 scribcd as occasionally occurring in old female 

 birds, is directly dependent, not upon their age, 

 but upon the state of the ovaries in them, 

 seems still further proved by similar changes 

 being sometimes observed in these females long 

 previous to the natural cessation of the powers 

 of reproduction, in consequence of their ovaries 

 having become wasted or destroyed by disease. 

 Greve,J in his Fragments of Comparative 

 Anatomy and Physiology, states that hens 

 whose ovaries are scirrhous crow sometimes 

 like cocks, acquire tail-feathers resembling 



Edinburgh Journ. of Philosoph. Science, (1826) 

 p. 308. 



t Rumball, in Home's Comparative Anatomy, 

 vol. iii. p. 330, stales having observed a.i old duck 

 which had assumed the male plumage, attempt 

 sexual connection with another female. This may 

 perhaps enable us to understand the reputed cases 

 of hermaphroditism in women, who, as (elated l>y 

 Mollerus (Tract, de Hermaphr. cap. ii.) and iUan- 

 card, (Collect. Medico- Phys. cent. iii. obs. 80,) 

 after having themselves borne children became ad- 

 dicted to intercourse with other females. Of course 

 we cannot give our credence to the alleged success- 

 ful issue of such intercourse. 



t Druchslueckc sur vcrgleich. Anut. und Physiol. 



S, !> > . 



those of the male, and become furnished with 

 large spurs. The same author mentions also 

 the case of a duck, which, from being previously 

 healthy, suddenly acquired the voice of the 

 male, and on dissection its ovary was found 

 hard, cartilaginous, and in part ossified. 



Mr. Yarrell, in a paper read before the Iloyal 

 Society in 1827,* has stated that in a immlxT 

 of instances he had observed young female 

 pheasants with plumage more or less resem- 

 bling the male, and in all of them he found on 

 dissection the ovaries in a very morbid state, 

 and the oviduct diseased throughout its whole 

 length, with its canal obliterated at its upper 

 part. lie also shews that a similar effect upon 

 the secondary sexual characters of the female 

 bird is produced by the artificial division and 

 removal of a small portion of their oviduct in 

 the operation of making capons of female poul- 

 try ; and he states that his investigations have 

 led him to believe that in all animals bearing 

 external characters indicative of the sex, these 

 characters will undergo a change and exhibit 

 an appearance intermediate between the perfect 

 male and female, wherever the system is de- 

 prived of the influence of the true sexual organs, 

 whether from original malformation, acquired 

 disease, or artificial obliteration^ 



From the frequency with which castration is 

 performed, the effects of the testicles in evol- 

 ving the general sexual peculiarities of the male 

 have been more accurately ascertained than 

 those of the ovaries upon the female consti- 

 tution. These effects vary according to the age 

 at which the removal of the testicles takes 

 place. When an animal is castrated some time 

 before it has reached the term of puberty, the 

 distinctive characters of the male are in general 

 never developed ; and the total absence of these 

 characters, together with the softness and re- 

 laxation of their tissues, the contour of their 

 form, the tone of their voice, and their want 

 of masculine energy and vigour, assimilate 

 them more in appearance and habits to the 

 female than to the male type. If the testicles 

 are removed nearer the period of puberty, or 

 at any time after that term has occurred, and 



Phil. Trans, for 1827, part ii. p. 268. 



t On old or diseased female birds assuming the 

 plumage, &c. of the male, sco J. Hunter, Observ. 

 on the An. Econ. p. 75 , E. Home, Lect. on Comp. 

 Anat. vol. iii. p. 329 ; Mauduit, in Encvcl. Method. 

 Art. Faimn, torn. 'ii. p. 3 ; Butter, in Wernerian 

 Soc. Mem. vol. iii. p. 183 ; Schneider's Notes, in 

 his edition of the Emperor Frederick the Second ' 

 Treatise " De Arte Venandi cum Avibus ;" Tucker's 

 Ornithologia Damnoniensis ; Catesby'a Natural 

 History of Carolina, &c. i. t. 1. ; Bcchslein, 

 Naturgeschichtc d. Deutschlands, bd. ii. 4 116; 

 Blumenbach, DC anomalis ct vitiosis quihusdam 

 nisus formativi aberrationibus, p. 8 ; and Instil, of 

 Physiology, p. 369; Payrandeau, Bull, dcs Sc. 

 Nat. t. xiii. p. 243 ; Tiedemann, Zoologie, vol. 

 iii. p. 306 ; Geoff. St. Hilaire, Phil. Anal. lorn. ii. 

 p. 360; Isid. St. Hilaire, Mem. du Mus. d'Hist. Nat. 

 torn. xti. p. 220 ; Annal. dcs Sc. Nat. t. vii. p. 336, 

 or Kdinbur^h Xrw Philosophical Journal for 1820', 

 p. 302, with additional cases by Professor Jameson, 

 p. 30!l; Kob, De mutatione sexus. p. 11. Berlin, 

 1823 ; Yarrell, Phil. Trans, for 1827, p. 268, with 

 a drawing of the diseased ovaries, &c. 



