282 MENTAL FACULTIES sec. 



would otherwise develop are devoured by two more favoured 

 larvae. 



But the case of the ostrich could only be employed as an 

 example of a reasoning instinct if it could be assumed that 

 the hens have come to co-operate in incubating a large 

 number of eggs with the intention of providing the first food 

 for their young. As the conditions of the case are not known 

 more minutely it is not possible to form an opinion upon it ; 

 but in any case it is intelligent instinct, or intelligent action, 

 when the ostriches make use of these eggs to feed their young ; 

 and I chose this example to bring into view the distinction 

 between the two kinds of mental action, as well as on account 

 of its interest, because it is little known, and because ostriches 

 are proverbially described as stupid animals. 



But what was it that taught the beaver to dam back 

 the flowing water by a regular weir built of tree trunks, 

 sticks, and branches, in order that some of the burrows 

 which lead to the face of the river-bank from the building 

 which it so skilfully constructs might be always under 

 water ? 



What taught the ants to carry on regular agricultural 

 operations, to collect the seeds of certain grasses, let them 

 germinate, then to bite off the germ — to malt, in fact, and to 

 dry the seeds, and keep them for future requirements ? What 

 taught them to keep slaves, and make these feed them, until 

 more than one species have forgotten how to feed themselves 

 by their own exertions ? 



I will not enter upon a minute consideration of the 

 wonderful facts presented to us by the social life of the 

 Hymenoptera, and especially by the ants. These facts, which 

 so strikingly illustrate instincts of reason, were long doubted, 

 but have been completely established, particularly by Forel, 

 who has fully confirmed the observations of Huber, and 

 largely added to them, in his excellent work. I need not 



