268 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 
automatic obedience as the intellect be- 
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. 
Intellect the 
choice of 
responses. 
