ANIMAL INDUSTRIES 137 



bottom to top with the nuts, the separate holes 

 being apparently made for convenience of access to 

 the column of nuts within. The intelligence which 

 not only constructs a special storehouse, but teaches 

 the woodpecker to lay by only the nuts which 

 will keep, and not the insects which would decay, 

 is perhaps the highest form of bird-reasoning which 

 has yet been observed. The common ant of Italy 

 inopte metuens formica senect<e of the Romans if 

 not so strangely ingenious as the gardener ants of 

 the tropics, which prepare a particular soil on which 

 to grow within their nests the fungus on which 

 alone they feed, exhibits what is probably the 

 most complex form of instinctive industry shown 

 by any European animal. It stores up oats and 

 various kinds of grain, making hundreds of little 

 rooms as granaries, of about the size of a watch. 

 But grain lying in the ground naturally germinates. 

 How the ants prevent this is not known. Probably 

 by ventilation, as bees ventilate their hives by 

 artificial draught. All that is certain is, that if 

 the ants are removed the grain sprouts. When the 

 ants wish to use the store, they allow the grains 

 to germinate, until the chemical change takes 

 place in the material which makes its fermenting juice 

 food suitable for their digestion. They then 

 arrest the process of change by destroying the 



