264 BREEDING 



almost identical witti that based on the changes 

 effected by the parasites in the crabs. In both cases 

 the male is bipotential and the female unipotential. 

 This is all the more remarkable when the profoundly 

 different nature of the phenomena from which the 

 conclusions are derived, in the two cases, is borne in 

 mind. 



It would be unprofitable in the present stage of 

 inquiry, when every inference ought to be regarded as 

 sub judice, to attempt to base a verdict on such 

 conflicting and insufficient evidence as that which 

 is at present obtainable. For the present it will 

 be sufficient to sum up the evidence which has been 

 considered. 



All four sets of evidence examined point to the 

 conclusion that one sex is bipotential and the other 

 unipotential. The first two, the clinical and the 

 Mendelian, point to the female as the heterozygote. 

 The last two point to the male as the heterozygote. 

 In estimating the relative value of the evidence in 

 these two sets of evidence it should be borne in mind 

 that in the case of the Mendelian and the clinical, 

 the conclusion is only reached by a long and devious 

 argumentative route ; it is as if the secret of the 

 constitution of the sexes were at the end of a winding 

 passage, and the glimpse we get of it by the Mendelian 

 and clinical methods is such a one as we might get 

 by the adjustment of mirrors in the passage so as to 

 see the far end of it. The conclusion is liable to be 

 falsified in proportion to the number of distinct steps 

 (where error may creep in) in the argument by which 



