APPOINTMENTS 87 



These and a score other gall-flies keep appointment 

 with the oak alone, and of all the other creatures to 

 which the oak is a kingdom we need only mention 

 the oak-weevil. It is now asleep in a sense unborn 

 and certainly without any intention of the part it is to 

 play. When the leaves are tender and pliable, whether 

 that be earlier or later than usual, the weevil will be 

 there with its cutting instruments and its foreknow- 

 ledge of the best way yet discovered of cutting to the 

 mid-rib, folding and rolling the leaf so that a com- 

 plete hanging shelter for its progeny shall be formed. 

 The cleverest man that, not having seen one of these 

 shelters, shall attempt to design one will find that the 

 weevil has improved on it. But here are wheels quite 

 beyond our comprehension. 



And is a simple fact like the migration of the red- 

 start within our comprehension? The nearest con- 

 ception we can get of the impulse that moves the 

 migrants at the right time is a kind of Hertzian-wave 

 apparatus born in each of them, and capable of re- 

 sponding to the same thermo-electric stimulus that 

 has moved its ancestors for untold generations. How 

 subtle and extra-material this impulse must be is 

 shown by the way in which it penetrates artificiality. 

 The Canadian goose moved to another hemisphere, 

 fed comfortably in a public park, even reared from 

 the egg in this country, yet raises its clipped wings 

 and makes ineffectual attempt to fly north what time 

 the descendants of its ancestors in North America are 

 hastening to their banquet of snails and crustaceans 

 in the pools of British Columbia. Or consider the 

 still stranger case of a fish that now looks like a 

 brown trout, which has been living for some years in 



