WHAT WE MIGHT EXPECT. 179 



the greatest exactness all the repetitions, stops, and 

 changes. The acquisition of this lesson had, however, 

 exhausted the whole of the magpie's stock of intellect, for it 

 made it forget everything it had learned before " (" Percy 

 Anecdotes," Instinct, p. 166). 



Or, perhaps, more seriously, the memory of every im- 

 pregnate ovum from which every ancestor of a mule, for 

 example, has sprung, has reverted to a very long period 

 of time during which its forefathers have been creatures 

 like that which it is itself now going to become : thus, 

 the impregnate ovum from which the mule's father was 

 developed remembered nothing but horse memories; 

 but it felt its faith in these supported by the recollec- 

 tion of a vast number of previous generations, in which 

 it was, to all intents and purposes, what it now is. In 

 like manner, the impregnate ovum from which the 

 mule's mother was developed would be backed by the 

 assurance that it had done what it is going to do now 

 a hundred thousand times already. All would thus 

 be plain sailing. A horse and a donkey would result. 

 These two are brought together; an impregnate ovum 

 is produced which finds an unusual conflict of memory 

 between the two lines of its ancestors, nevertheless, being 

 accustomed to some conflict, it manages to get over the 

 difficulty, as on either side it finds itself backed by a very 

 long series of sufficiently steady memory. A mule results 

 a creature so distinctly different from either horse or 

 donkey, that reproduction is baffled, owing to the crea- 

 ture's having nothing but its own knowledge of itself 

 to fall back upon, behind which there comes an imme- 

 diate dislocation, or fault of memory, which is sufficient 



