DETERMINATION OF SEX 11 



Similarly it has been shown by Cuenot * that the Sex-determ- 

 differentiation of the gonads of maggots does not occur goquontiy to 

 until the end of larval life. This observer found, fertilization. 

 however, that the ultimate determination of sex in these 

 creatures was not influenced by nutrition. 



For further biological details concerning the determ- 

 ination of sex the writings of Morgan 2 , Marshall 3 , 

 Geddes and Thomson 4 and Doncaster 5 , to which I am 

 largely indebted, may be consulted. 



In spite of all the information at our disposal, we Uncertainty 

 must confess that the primary cause of sex-determination knowledge. 

 is not definitely known, and at the same time express 

 the opinion that since it is purely a physical question 

 observations on animals will no doubt some day lead 

 to a complete understanding of this matter. It is quite 

 possible that there is more than one deciding factor. 

 Meanwhile, it appears that no one view alone covers all 

 the requirements, but that the truth is probably wider, 

 and that many of the theories are correct so far as they 

 go ; and that there is some truth in most of the views 

 for which there is biological evidence, but not the whole 

 truth in any one. 



At present in regard to the human species we only Every fertn- 

 know, from pathological and clinical observations, that i n the human 

 there must be a latent but predominating tendency m b ^uai S 

 every fertilized ovum towards masculinity or femininity, 

 and that every fertilized ovum is potentially bisexual. 

 It is obvious to all that in every person there is pre- 

 dominating masculinity or femininity, which decides the 

 sex-denomination ; but, at the same time, it is equally 

 obvious that latent traits of the opposite sex are always 



1 Cuenot, L., Bull. Sci. de France et Belg., 1899, vol. xxxii, p. 462. 



2 Morgan, T. H., Experimental Zoology, Lond., 1907, p. 363. 



3 Marshall, F. H. A., The Physiology of Reproduction, Lond., 1910, 

 p. 623. 



* Geddes, P., and J. A. Thomson, The Evolution of Sex, 1901, 

 Revised ed. 



5 Doncaster, L., The Determination of Sex, 1914. 



