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Show INHERITANCE. CHAP. XIII. 50 . h' h h e not been cultivated, hybrid plants raised from spemes w IC av lt' t d they are of whilst with those which have been long cu r;a e ' . d' ' . 1 · explams a cunous IS- fre uent occurrence. This cone uswn ' . · q . Max WI.C hura w wh o wor· ked exclusively on willow· s, crepancy · ' d lt e never saw an m-which had not been subjecte to cuf ~r 'to suspect that the f · . ncl he goes so ar as stance o reversiOn' a . rotected his hybrids from careful Gartner had not sufficiently p . h th h d ' . N audm on t e o er an ' the pollen of th~ pare~t-speCies ~bitaceou; and other cultivated who chiefly expenmente on cucur other author on the plants, insists mor~ str~nuou~y b~:~: a~e conclusion that the tendency to reversiOn m all_ Y · ed b culture, is one condition of the parent-speCies, as affect'on Igrees fairly well . t s leading to reversi , of the proxima e cause . d nimals and cultivated with the converse case of domesticate a e feral· for l nts bein liable to reversion when th~y b_ecom ' . P a g . t' on or constitutiOn must be dis-in both cases the orgamsa I b d th gh in a very different way. . turF 'e ' lly ouw e h ave seen that characters often reappea. r m ma ' . 'thout our being able to assign any proximate purely-bred rahces wt~ become feral this is either indirectly or cause· but w en ey · · f lif W'th . ' . d d b the change in their conditiOns o e. I duect7: u;e th~ act of crossing in itself certainly leads to crosse ree sf, l lost characters as well as of those derived the recovery o ong- · ' . . t from either parent-form. Oha~~ed conditions, consequen on lt. t' and the relative positiOn of buds, flowers, and seeds cu Iva wn, · · th · e tendency on the lant, all apparently aid in givmg IS sam . . Reversi.O pn may occur. ei' the r. through semi.n al or bud generaft iOn, erally at birth, but sometimes only with an advance o age. gen t' of the individual may alone be thus Segments or por wns . · t · b . h uld be born resemblmg m cer am affected. That a emg s 0 d in some characters an ancestor removed by two or thr~e, a~ . b hundreds or even thousands of generatwns, IS assured~y cases dY f 1 fact. In these cases the ch I'l d I·S comm only said a won er u · d rents or to inherit such characters directly from Its gran pa . bl more remote ancestors. But this view is hai:dly c?nceiva e. If, however, we suppose that every character IS denved exclu- 23 For Gartner's so 'Die Bastardbcfruchtung .... der Weiden,' 1865, s. . remarks on this head, see , Bastarderzeugung,' s. 474, 582. CliAP. XIII. REVERSION. 51 sively from the father or mother, but that many characters lie latent in both parents during a long succession of generations, the foregoing facts are intelligible. In what manner characters may be conceived to lie latent, will be considered in a future chapter to which I have lately alluded. Latent Characters. -But I must explain what is meant by characters lying latent. The most obvious illustr~tion is afforded by secondary sexual characters. In every female all the secondary male characters, and in every male all the secondary female characters, apparently exist in a latent state, ready to be evolved under certain conditions. It is well known that a large number of female birds, such as fowls, various pheasants, partridges, peahens, ducks, &c., when old or diseased, or when operated on, partly assume the secondary male characters of their species. In the case of the hen-pheasant this has been observed to occur far more frequently during certain seasons than during others.51 A duck ten years old has been known to assun;e both the perfect winter and summer plumage of the drake.52 V\Taterton 53 gives a curious case of a hen which had ceased laying, and had assumed the plumage, voice, spurs, and warlike disposition of the cock; when opposed to an enemy she would erect her hackles and show fight. Thus every character, even to the instinct and manner of fighting, must have lain dormant in this hen as long as her ovaria continued to act. The females of two kinds of deer, when old, have been known to acquire horns; and, as Hunter has remarked, we see something of an analogous nature in the human species. On the other hand, with male animals, it is notorious that the secondary sexual characters are more or less completely lost when they are subjected to castration. Thus, if the operation be performed on a young cock, he never, as Yan·ell states, crows 51 Yarrell, 'Phil. Transact.,' 1827, p. 268; Dr. Hamilton, in 1 Proc. Zoolog. Soc.,' 1862, p. 23. 52 ' Archiv. Skand. Beitrage zur Naturgesch,' viii. s. 397-413. sa In his' Essays on Nat. Hist.,' 1838. Mr. Hewitt gives analogous cases with hen-pheasants in 'Journal of Horticulture,' July 12, 1864, p. 37. Isidore Geoffroy Saint Hilaire, in his 1 Essais de Zoolog. Gen.' (suites a Buffon, 1842, pp. 496-513), has collected such cases in ten different kinds of birds. It appears that Aristotle was well aware of the change in mental disposition in old hens. The case of the female deer acquiring horns is given at p. 513. E 2 |