384 HELEN DEAN KING 



to a litter containing seven young. The sex of only five of these 

 individuals was ascertained; four of them were females, and one a 

 male. The female lacking the left ovary produced a litter of 

 five young, of which three were males and two were females. 

 The breeding females were killed soon after the birth of their 

 litters and dissected. Each was found to lack the ovary and part 

 of the fallopian tube on the side of the body that had been oper- 

 ated upon. These experiments are not open to criticism on 

 account of the manner in which they were carried out, and the 

 results show very conclusively that, in the albino rat, eggs cap- 

 able of developing into individuals of either sex can come from 

 either ovary. Doncaster and Marshall rightly argue that 

 because Dawson's theory is not valid for the rat is not a proof 

 that it is also invalid for man; but they believe, as do probably 

 most investigators, that ''definite proof for another mammal 

 detracts from its probability." Various cases in which one-sided 

 ovariotomy in woman has been necessitated by disease have fur- 

 nished evidence against the theories of von Seligson, of Dawson 

 and of Calhoun that is fully as convincing as is that which the 

 experiments of Doncaster and Marshall give for the albino rat. 

 A number of investigators, among whom may be mentioned 

 Rauber ('00), Beard ('02), Schultze ('03) and Russo ('09), main- 

 tain that sex is determined in the ovary, although they do not 

 believe that the male-producing eggs are segregated in the right 

 ovary and that the female-producing eggs are all contained in 

 the left ovary. This theory has a considerable amount of evi- 

 dence in its favor, and if it be true, it is evident, as Schultze ('03) 

 has stated, that "in der Ovogenese ist die Losung der Geschlechts- 

 bildung enthalten." No advocate of this theory has ventured a 

 suggestion as to the relative distribution of the male-producing 

 and of the female-producing eggs in each ovary, and there is the 

 possibility that eggs of one kind may be produced in much greater 

 numbers in one ovary than in the other. On the current hypoth- 

 esis that spermatozoa are dimorphic and that the male determines 

 sex, the possibility also exists that many more spermatozoa of 

 one kind are produced in one testicle than in the other. If there 

 is a constant difference in the relative distribution of the various 



