LESWEAK SOCIETY OF LONDON. XV 



spring, but that sometimes this first cross will be undistinguish- 

 able from one parent. Grodrou does not touch upon this circum- 

 stance, so opposed to the rules by which, in his ' Flora,' he had 

 practically established the parentage of the hybrids described ; but 

 having observed that whilst, by fecundating ^gilops ovata with 

 wheat, he never failed to produce the intermediate ^. triticoides, 

 all his fecundations of wheat by ^gilops, repeated upon several 

 varieties of wheat during five successive years, produced invariably 

 nothing but wheat, he explains this anomaly by supposing that 

 his precautions were always insufficient for preventing simulta- 

 neous fecundation by neighbouring wheat-flowers. I allude to 

 these facts only as showing with what care experiments of this 

 kind must be repeated, so as not, on the one hand, too hastily to 

 oppose the evidence of our senses to reason from analogy, nor, on 

 the other, to allow general theory to overrule actual experience. 



With regard to animals, in the references to the subject which 

 Dr. Sclater has kindly pointed out to me, I find nothing new on 

 the fertility of hybrids, except a short notice by Mr. Newton, in 

 the ' Proceedings of the Zoological Society ' (1860, p. 338), of a 

 pair of hybrids between a Pintail Drake and a farmyard Duck, 

 producing four ducklings ; but, in the next generation, the ferti- 

 lity ceased, instead of increasing as in many plants. 



Almost all experiments and observations upon hybridism have 

 been upon plants in a state of cultivation, or animals in domesticity. 

 In the wUd state there is this difference, that exceptionally fertile 

 hybrids must be still more rare ; for to the obstacles opposed by 

 sterility, or return to parent forms (or, say, disjunction of parent 

 essences), to the establishment of new hybrid races, must be added 

 the destruction ensuing from the want of the protection and 

 assistance afforded by human care. Of this a curious instance 

 is mentioned by M. Grodron, in accounting for the rarity in a wild 

 state of the u3Egilops speltcBformis, which seeds so readily under 

 cultivation : the structure of the spike is such as to render the 

 germination of the seed exceedingly difficult without extraneous 

 aid in forcing it into the ground. All tends to confirm the now 

 generally received opinion, that although hybridism in a wUd state 

 between races sufficiently distinct to be fairly called species is not 

 unfi-equent, the individuals are few, and generally differ from each 

 other as much as they do from either parent. The modern 

 practice, therefore, of giving names and descriptions of these hy- 

 brids as of distinct races cannot be too much deprecated : it is 

 an attempt to give fixity to that which has none, confounding 



