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 f emiaine 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.^ 



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,^ 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 Inachus, Smith 

 suggested ^hat in the male affected by Sacculina the assumption of 

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

 (or female generative substance) similar to that normally elaborated 



' For further information see Krafft-Ebing, Psychopathia Sexicalis, Stuttgart, 

 1882; Havelock Ellis, Stvdies in the Psychology of Sex: Sexual Inversion, 

 Philadelpliia, 1901 ; Forel, The Sexual Question, English Translation, London, 

 1908 ; and Bloch, The Sexual Life of our Time, English Translation, London, 

 1908. For a discussion on the distinctions between men and women, see 

 Manouvrier, " Conclusions g6n6rales sur I'Anthropologie des Sexes et Applica- 

 tions sociales," Rev. de Vicole dl Anthropologie de Paris, 1909 ; Havelock Ellis, 

 Man and Woman, 5th Edition, London, 1914, and Bucura, GescJdechtsunterschiede 

 hewn Mensohen, eine Klinisch-physiologische Studie, Wien, 1913. 



2 Potts, "The Modification of the Sexual Characters of the Hermit Crab, 

 ete.," Qimr. Jour. Micr. Science, vol. 1., 1906. (See p. 326, Chapter IX.) 



^ Smith (G.), " Sex in the Crustacea, etc.," British Association Report, 

 Leicester Meeting, 1907 ; " Studies in the Experimental Analysis of Sex," Quar. 

 Jour. Micr. Science, vols. liv. and Iv., 1910. 



