128 INTRODUCTION TO SEXUAL PHYSIOLOGY 



enlarged aiul became enveloped in a prei)iice. Apart altogether 

 from the essential generative organs there are all degrees of 

 somatic and psychical intersexuality in man, as instanced by 

 the sapphist and the virago, on the one hand, and the effeminate 

 man on the other. Moreover, some authorities regard liomo- 

 sexuality as an intersexual condition. 



Among the lower mammals intersexuality has been especially 

 noted in pigs and goats. Pick examined half a million pii]js in 

 the Berlin slaughterhouse and found six cases of true glandidar 

 hermaphroditism. Krediet has described a goat with a definite 

 ovario-testis. Numerous cases of intersexuality in horses, 

 cattle, sheep, goats, and })igs have been described by Crew. 

 The genital organs generally consisted of a testicidar gland 

 with tubules and interstitial tissue (but witliout si)erniatozoa), 

 vasa deferentia, vesicula), a prostate, an enlarged clitoris, a uterus, 

 and a vagina. Many of them were probably cases in which 

 sex reversal had taken place, the ovarian tissue having atrophietl. 

 Hanmiond has })resented evidence of reversal in rabbits, the 

 ovaries containing structures suggestive of incipient semini- 

 ferous tubules. In some individuals (human and other) the 

 masculinisation of a female was associated with an abnormal 

 growth (hypernephroma or neoplasm) in the suprarenal glands. 



Among birds sex reversal appears to be commoner. A 

 number of instances of sex change have been recently describeil 

 (Pearl and Boring, Crew, Hartman and Hamilton, etc.). Miss 

 Fell has given an account of the niicrosco])ical structure of lien's 

 ovaries, showing sperm formation after sex reversal had set in. 

 In one of these the hen had formerly laid many eggs, which duly 

 hatched into chicks, but she afterwards changed into a functional 

 cock, and became the father of two chickens. The so-called 

 " cock-feathering " of old birds has long been known, and Gurney 

 has described its occurrence in twenty-six species. Darwin also 

 alluded to the crowing of old hens and other similar phenomena. 



Sex reversal may relate also to the mating habits of birds under 

 natural conditions, for in the crested grebe Julian Huxley has 

 described the male as sometimes adopting the position of the 

 female and vice versa, and the same thing has been seen 

 exceptionally with })igeons. 



Various degrees of hermaphroditism in Amphibia have long 

 been known, and hermaphrodite frogs have often been described. 



