A CRITICAL AXD STATISTJCAT^ STUDY OF THE 

 DETERMIXA'llOX OF SKX. I ARTICL L.\RLY 

 L\ IIl'MAX ()lTSl'inX(;.' 



F. H. PIKi:. 

 I. Introductiox. 



Cu£not ('99) and Strasburger (:00) summarized the evidence 

 in favor of the heredity of sex in animals and plants, respectively. 

 Rauber (:00) in the same year as Strasburger, declared for the 

 heredity of sex in man. 



Bateson in 1902 suggested that the ISIendelian law might apply 

 to the heredity of sex. Castle (:03), accepting Cuenot's and 

 Strasburger's views without question, formulated an hypothesis 

 to account for the heredity of sex in accordance with ^Mendel's 

 law. Weldon (:01) had already shown that ^Mendel's original 

 results with cotyledon color in peas differed from the theoretical 

 numbers by something less than the limits of error. At the time 

 Castle's theory ap])eare(], it occurred to nic to gatlicr statistics 

 of births in order to (letcriiiiiic in a similar way the probaliility 

 that the actual inimhcrs of male and tVinalc l)irtlis would he the 

 numbers deinaiulcd by the hypothesis. 



II. Rkview of Previous Work. 



The idea that the sex of the offspring could be influenced by 

 changing the environment of the parents or of the very young 

 embryo has long been current, "^^ing's ('S3) experiments on 

 tadpoles, in which he was apparently able to control the sex by 



' This study was begun under the direction ..f Pn.f.-M.r C. !I. luarmnunn 

 of the Department of Zoologj' of Indiana rniv.M>ity an<l \Na^ roinplrted in 

 the Hull Physiological Laboratory- of tlu- I nivcrMiy ui ( hi.a-o, Ti,r author 

 desires to express his obligations „. th. lualtl. .mI,,-..,-. an.l n-i^tra.-who 

 have supplied hi.n with statisti..; ^t.. hi^ ..„ll,.a.ni.. u, tb. Hull Lalx,nUo:y for 



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