TABOO AND GENETICS 71 



The peculiar complication of the chemical 

 complex determining sex in these mammalian 

 Sorms, involving all the glands and hence the 

 entire body, makes it problematical whether a 

 complete (functional) reversal is possible, at 

 least after any development whatever of the 

 embryo has taken place. On the other hand, 

 the fact that such complete transformations 

 have not so far been observed by no means 

 proves their non-existence. Their being func- 

 tional, and hence to all external appearances 

 normal, would cause such animals to escape 

 observation. 



Latent traits of the opposite sex of course 

 immediately suggest recessive or unexpressed 

 characters in the well-known Mendelian in- 

 heritance phenomena. In the bird-castration 

 cases, we saw that to remove the inhibiting sex 

 glands caused previously latent characters to 

 act like dominant or expressed ones. The case 

 of horns in sheep, investigated by Professor 

 Wood (16), is so similar that it seems worth 

 summarizing, by way of illustration. 



Both sexes in Dorset sheep have well-developed 

 horns ; in the Suffolk breed both sexes are 

 hornless. If the breeds are crossed, all the 

 rams in the first (hybrid) generation have horns 

 and all the ewes are hornless. If these hybrids 

 are mated, the resulting male offspring averages 

 three horned to one hornless ; but the females 



