2 68 FOOT-NOTES TO EVOLUTION. 



Michigan, can not escape from it because they have not 

 intelligence enough to find the opening through which 

 they have entered. If, however, a loon enters the net 

 the fishes become frightened and " lose their heads." 

 In this case they will sooner or later all escape, for they 

 cease to hunt about ineffectively for an opening, and 

 flee automatically in straight lines, and these straight 

 lines will in time bring them to the open door of the net. 

 Wild animals learn to avoid poisonous plants by in- 

 stinct. Those who have not an inherited dislike for 

 these plants perish. When the animals are brought into 

 contact with vegetation unknown to their ancestors this 

 instinct fails them. Hence arises in California the dan- 

 ger from " loco weeds," as certain species of wild vetches 

 are called. These plants produce temporary or per- 

 manent insanity or paralysis of nerve centres. The 

 native ponies avoid them, but imported animals do not, 

 and often fall victims to their nerve-poisoning influ- 

 ence. In the long run, only those survive who dislike 

 the " loco-weed " and avoid it instinctively. 



The confusion of highly perfected instinct with in- 

 tellect is very common in popular discussions. Instinct 

 grows weak and less accurate in its 

 Intellect the automatic obedience as the intellect be- 



choice of ....... -r. i 



comes available in its place. Both in- 

 tellect and instinct are outgrowths from 

 the simple reflex response to external conditions. But 

 instinct insures a single definite response to the cor- 

 responding stimulus. The intellect has a choice of re- 

 sponses. In its lower stages it is vacillating and inef- 

 fective ; but as its development goes on it becomes 

 alert and adequate to the varied conditions of life. It 

 grows with the need for improvement. It will therefore 

 become impossible for the complexity of life to outgrow 

 the adequacy of man to adapt himself to its conditions. 



