THE FACTORS WHICH DETERMINE SEX 691 



are women with ill-developed breasts who in other respects are 

 typical females. There exist all transitional forms from the most 

 masculine male to the most effeminate male, and on the other side, 

 from the sapphist and the virago to the most feminine female ; but 

 in man the characters of one sex are always dominant, though the 

 degree of dominance varies through considerable limits. On this 

 view, the phenomena of so-called sexual inversion and homosexuality, 

 which are ordinarily regarded as purely pathological, are in reality 

 psychological manifestations of special characters belonging to the 

 recessive sex. 1 



Such cases as those cited above have led Castle, Heape, and others 

 to conclude that all animals and plants are potentially hermaphrodite, 

 inasmuch as they contain the characters of both sexes, although 

 ordinarily the characters of one sex only are developed, while those 

 of the other are either latent or imperfectly developed. 



Castle has cited cases from among plants in which the characters 

 of one sex can be induced to appear by the artificial destruction of 

 those of the other. Examples of the same kind of phenomenon are 

 supplied by certain animals. Thus Potts- has shown that in the 

 male Hermit Crab ova make their appearance in the testes, and the 

 secondary sexual characters become modified in the direction of the 

 female as a consequence of the animal being affected by the parasite 

 Peltogaster. Similar changes occur in a number of other animals 

 belonging to widely different groups, but they are especially common 

 in the Crustacea. Geoffrey Smith, who has paid considerable attention 

 to this subject, 3 explained the phenomenon by assuming that the 

 males, in order to cope with the drain on the system caused by the 

 parasites, have to increase their vegetative activity, and that they do 

 this by suppressing their male organisations and calling into play the 

 female ones, which they possess in a latent condition. 



In a later paper on the sex - metabolism of Tnachus, Smith 

 suggested that in the male affected by Sacculina the assumption of 

 female characters is due to the formation of a yolk-forming sn Instance 

 (or female generative substance) similar to that normally elaborated 



1 For further information see Kratlt-Kliinu', /'>//./-.,////,/./ >'.-/, ///.<. Stuttgart, 

 1882; Havelock Ellis, Studies in tli- /'.<//./,,./</// ;/' Seat: Sexual // 

 Philadelphia, 1901 ; Forel, Tin- ,SV. ,-/,// ^//-.^/,,,/, Bnglilb Translation, London, 

 1!>08 ; and Bloch, 7V- >'.--/.// /,//; ,,/' owr 7V/,/.. Kn^lish Translation, London, 

 1908. For a discussion on the distinctions lietwivn mm and women, -c.- 

 Manouvrier, "Conclusions gencralrs snr PA&tliropoIogie des Sf.\c- <-\ Applica- 

 tions sociales," l&v.de /"A* -./- -/'.I /,////./ //,/ /, ,/- /',/,/., |!M)<; Ua\cl<-k Kllis, 

 )l,in.<nnl \\'ni,i<ni, .~>th Kdition, London, !!]-!, and I'.ucnra, < ;.:<.-t,l.:-l,t,< ,,t<-, W-/W/,. 

 ix'im JfeiwJtei', '// AV////.W, -///-//../'/.A/-//.*. /,< ."//.. Wien, I It 13. 



2 Potts, "The Modification of the Sexual < 'haiactrrs of tli-- Hermit Crab, 

 te.," Quar. Jnr. Mi<;: ,SW- /-, vol. 1., l!Hx;. (S.-.- p. .Si'f!, Chapter IX.) 



3 Smith ((i.), "Sex in the Crustacea, etc.,' /;//'//.</ . I ...<. /<///-.,- /,'/*>/, 

 Leicester Meeting, 1907 ; " Studies in the Experimental Anal\>i- of Sex, Qttar. 

 Join: .(/' x . vols. liv. and lv., 1910. 



