220 The Outline of Science 



of intelligence what is merely the outcome of long-continued 

 structure adaptation. When the limbless lizard called the Slow- 

 worm is suddenly seized by the tail, it escapes by surrendering the 

 appendage, which breaks across a preformed weak plane. But 

 this is a reflex action, not a reflective one. It is comparable to 

 our sudden withdrawal of our finger from a very hot cinder. The 

 Egg-eating African snake Dasypeltis gets the egg of a bird into 

 its gullet unbroken, and cuts the shell against downward-project- 

 ing sharp points of the vertebra?. None of the precious contents 

 is lost and the broken "empties" are returned. It is admirable, 

 indeed unsurpassable ; but it is not intelligent. 



5 



Mind in Birds 



Sight and hearing are highly developed in birds, and the 

 senses, besides pulling the triggers of inborn efficiencies, supply 

 the raw materials for intelligence. There is some truth, though 

 not the whole truth, in the old philosophical dictum, that there is 

 nothing in the intellect which was not previously in the senses. 

 Many people have admired the certainty and alacrity with which 

 gulls pick up a fragment of biscuit from the white wake of a 

 steamer, and the incident is characteristic. In their power of 

 rapidly altering the focus of the eye, birds are unsurpassed. 



To the sense of sight in birds, the sense of hearing comes 

 a good second. A twig breaks under our feet, and out sounds 

 the danger-call of the bird we were trying to watch. Many young 

 birds, like partridges, respond when two or three hours old to the 

 anxious warning note of the parents, and squat motionless on the 

 ground, though other sounds, such as the excited clucking of a 

 foster-mother hen, leave them indifferent. They do not know 

 what they are doing when they squat ; they are obeying the living 

 hand of the past which is within them. Their behaviour is instinc- 

 tive. But the present point is the discriminating quality of the 

 sense of hearing ; and that is corroborated by the singing of birds. 



