254 THE WONDER OF LIFE 



' offspring ', who could not, of course, follow her when she 

 occasionally flew off the nest and summoned them. After 

 one day she was quite aware of the meaning of the ferrets' 

 hoarse cries, so different from a chick's piping note, and 

 she would run in an agitated manner to any near place 

 where Mr. Romanes hid them. There was no evidence, 

 however, of a reciprocal understanding, for the ferrets 

 showed no responsiveness to the hen's clucking. 



During the whole fortnight the hen sat almost con- 

 tinuously. 



' She used to comb out their hair with her bill, in the 

 same way as hens in general comb out the feathers of their 

 chickens. While engaged in this process, however, she 

 used frequently to stop and look with one eye at the 

 wriggling nest-full with an inquiring gaze expressive of 

 astonishment. At other times, also, her family gave her 

 good reason to be surprised ; for she used often to fly off 

 the nest suddenly with a loud scream — an action which 

 was doubtless due to the unaccustomed sensation of being 

 nipped by the young ferrets in their search for the teats ' 



This interesting case has many parallels, and the series 

 of them afford astonishing illustrations of the plasticity 

 of instinct. 



Educated Animals 



When we study horses, elephants, dogs, cats, monkeys, 

 and other ' clever ' Mammals, it seems necessary to admit 

 that they have good memories, that they have a power of 

 rapidly forming associations, that they profit by experience, 

 that they can adapt old means to new ends, that they can 

 ' put two and two together '. They must be granted the 

 power of perceptual inference, and there are some facts con- 



