132 THE WHENCE AND THE WHITHER OF MAN 



freedom of action by means of a stronger locomotive 

 system is bringing continually new and varied expe- 

 riences. And if, as in vertebrates, longer life be added, 

 frequent repetition of the experience deepens the im- 

 pression. Slowly, as if tentatively, the animal begins 

 to modify some of its instincts, at first only in slight 

 details, or to adopt new lines of action not included in 

 its old instincts, but suited to the new emergencies. 

 This is the dawn of intelligence. Its beginnings still 

 remain undiscovered. Mr. Darwin believes that traces 

 of it can be found in earthworms and other annelids. 

 He also tells us that oysters taken from a depth never 

 uncovered by the sea, and transported inland, open 

 their shells, lose the contained water, and die ; but 

 that left in reservoirs, where they are occasionally left 

 uncovered for a short time, they learn to keep their 

 shells shut, and live for a much longer time when re- 

 moved from the water. If oysters can learn by expe- 

 rience, lower worms probably can do the same. 



Certain experiments made on sea-anemones, actinse 

 animals a little more highly organized than hydra, de- 

 mand repetition under careful observation.* The ob- 

 server placed on one of the tentacles of a sea-anemone 

 a bit of paper which had been dipped in beef -juice. 

 It was seized and carried to the mouth and here dis- 

 carded. This tentacle after one or two experiments 

 refused to have anything more to do with it. But 

 other tentacles could be successively cheated. The 

 nerve-cells governing each tentacle appear to have 

 been able to learn by experience, but each group in 

 the diffuse nervous system had to learn separately. 



* These experiments have been continued with most interesting and val- 

 uable results by Dr. G. H. Parker, of Harvard University. 



