44o POPULAR SCIENCE MONTHLY. 



and the sand with which it was mixed, and swallowed it all, and then 

 stuffed the shell itself into his mouth. This act was not instinctive. 

 It was the work of pure reason. Evidently his race was not familiar 

 with the use of eggs. Reason is an inefficient agent at first, a weak 

 tool; but when it is trained it becomes an agent more valuable and 

 more powerful than any instinct. 



The monkey Jocko tried to eat the egg offered him in much the 

 same way that Bob did, but, not liking the taste, he threw the whole 

 thing away. 



The low intelligence of the lower animals — as the fishes — may 

 be at times worse than none at all. If mental development were a 

 real advantage to fishes it would take place through natural selec- 

 tion. The fishes taken in a large pound net, as I have observed them 

 in Lake Michigan, can not escape from it because they have not intel- 

 ligence 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, but 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 instinct. 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 

 danger from " loco weeds," as certain species of wild vetches are 

 called. These plants produce temporary or permanent insanity .or 

 paralysis of nerve centers. The native ponies avoid them, but im- 

 ported animals do not, and often fall victims to their nerve-poisoning 

 influence. 



The confusion of highly perfected instinct with intellect is very 

 common in popular science. The instinct grows weak and less 

 accurate in its automatic obedience as the intellect becomes available 

 in its place. Both intellect and instinct are outgrowths from the 

 simple reflex response to external conditions. But the instinct in- 

 sures a single definite response to the corresponding stimulus. The 

 intellect has a choice of responses. In its lower stages it is vacillat- 

 ing and ineffective; but as its development goes on it becomes alert, 

 and adequate to the varied conditions of life. It rises with the need 

 for improvement. It will therefore become impossible for the com- 

 plexity of life to outgrow the adequacy of man to adapt himself to its 

 conditions. 



Many animals currently believed to be of high intelligence are 

 not so. The fur seal, just mentioned, for example, finds its way back 

 from the long swim of two or three thousand miles through a foggy 



