SEX CONTROL IN PIGEONS 



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marvels of selective power that may be exhibited by the 

 sex chromosomes, and to feel that even the above difficult 

 formula remains for them a possibility, we may refer to 

 the decisive data obtained in studies on the sex behavior 

 of the birds which are hatched from such a sex-controlled 

 series. We shall there see that those data differentiate 

 several grades of females. Some are quite nearly males, 

 —though they lay eggs. Is it too hazardous to suggest 

 that in one and the same egg the Y could hardly have 

 "gone out" to allow the egg to develop into a female, 

 and yet have "stayed in" in order to deliver the rela- 

 tive masculinity that we easily detect and measure? If 

 sex is directly the creature of a sex chromosome, the sex 

 situation found in some of my female doves requires that 

 the male-producing chromosome be eliminated from, and 

 retained in, one and the same egg ! The only alternative 

 that it is within my power to imagine is that in addition 

 to the selective elimination of the Y's during autumn, 

 there be further postulated a gradual fractional elim- 

 ination of parts of this chromosome, larger and larger 

 parts being eliminated during the progress of the season. 

 Or, that the reverse of this occurs, namely that the Y, 

 during the progress of the season, gradually adds some- 

 thing of X quality to itself, finally becoming more X 

 than Y. For those who would value this interpretation 

 I have no evidence or word of contradiction. The fact 

 must always remain that our procedures have not only 

 produced male and female from ova of opposed initial 

 tendency— largely under control— but that several grades 

 of intermediate sex have also been produced. 7 



iean Society of Zoologists and elsewhere, have clearly stated this result. 



Carnegie Year Bool; No 1913 (p.' 322), Eeport of Year 's Work. ' < The 

 results strongly indicate that the hereditary basis of sex (and, therefore, 



and alte 7 rnative\T^ Science, N. Z Vol. 39, 



No. 1003, Mar., 1914 (p. 440), "A Quantitative Basis of Sex as Indicated 

 by the Sex Behavior of Doves from a Sex Controlled Series." "These . . . 

 results together with our very abundant data on the storage metabolism of 

 the ova of these forms, and the initial fact of sex-control itself, strongly 



