SEX EATIO OF THE ALBINO RAT 383 



son. Many of the writers of these papers stated their beUef in 

 the theory that sex is determined in the ovary, but very few of 

 them put any faith whatever in von SeHgson's contention that 

 male eggs are segregated in the right ovary and that female eggs 

 are produced only in the left ovary. 



Goenner ('96) repeated von Seligson's experiments on rabbits, 

 and also extended them. He removed one testicle from each of 

 four males and one ovary from each of five females, all of the ani- 

 mals being about six months old when the operation was per- 

 formed. From the various matings in which animals were paired 

 that lacked the gonad on the same side of the body Goenner 

 obtained only three litters, each of which contained both males 

 and females. Four of the 16* young contained in these litters 

 died before their sex was ascertained; of the remaining 12 animals, 

 four were females and eight were males. These results indicate 

 that von Seligson did not properly distinguish the sexes of the 

 individuals in the various litters that he examined; but they do 

 not give convincing evidence against his theory, since unfortun- 

 ately Goenner does not state whether he killed the females and 

 ascertained if the gonads had been entirely removed by the oper- 

 ation. 



Dawson's revival of the right and left ovary hypothesis for man 

 has one important modification: the spermatozoan is not con- 

 sidered to have any influence whatever in determining sex. 

 According to Dawson's theory, therefore, spermatozoa from 

 either testicle are able to fertilize eggs from either ovary. Cal- 

 houn is of the opinion that the spermatozoan may possibly have 

 something to do with sex, and she suggests that this matter be 

 investigated experimentally. Evidently this writer is unac- 

 quainted with much of the literature dealing with the question 

 of sex-determination in the higher forms. 



In order to test the truth of Dawson's hypothesis, Doncaster 

 and Marshall ('10) made a small series of experiments last spring 

 on the albino rat. One female was spayed on the right side, and 

 a second one on the left. As soon as these rats had recovered 

 from the effects of the operation, they were mated with normal 

 males. The female that was spayed on the right side gave birth 



