STERILITY OF HYBRIDS. 411 



It is in pursuance of this design, to show " how igno- 

 rant we are," and thus to weaken the force of the prin- 

 cipal objection to his theory; that he, in his different 

 works, devotes such an amount of space, to the many- 

 instances of crossing and of close-interbreeding, of 

 which "we are so ignorant." 



It is with this same design^ that he says (p. 462, Vol. 

 ii, Animals and Plants, &c.) : 



"With respect to the sterility of hybrids, produced 

 from the union of two distinct species, it was shown in 

 the xixth chapter, that this depends exclusively on the 

 reproductive organs being specially affected; but, why 

 these organs should be thus affected, we do not know 

 any more (sic) than why unnatural conditions of life, 

 though compatible with health, should cause sterility, 

 or why continued close-interbreeding, or the illegiti- 

 mate union of dimorphic or trimorphic plants should 

 induce the same result." 



The idea he wishes to convey, is, that the whole 

 subject of sterility and of fertility, forms such an inex- 

 tricable maze, that it is presumption, in any one, to 

 say, that any aspect of the question, either rebuts, or 

 confirms, any theory. In other words : instead of ex- 

 plaining anything to his readers, he demands of them 

 to give up, for his gratification, the little positive knowl- 

 edge they have upon the subject, merely because there 

 is quite a number of similar orders of facts which seem 

 inexplicable! It is a curious feature, discernible 

 throughout all of Darwin's works purporting to prove 

 the evolution of the species, that his hypothesis abso- 

 lutely demands, that an embargo should be laid on the 

 acquisition of any knowledge of the cause of any class 



