VIII 

 THE EDUCABILITY OF A SNAIL 



IT has been well established that a common 

 garden-snail can find its way home over difficult 

 country from a distance of six yards or more. 

 Of one that habitually spent the day in a hole in 

 a garden wall, about four feet from the ground, 

 it is recorded that for months it utilized as a noc- 

 turnal ladder a piece of wood sloping from a bed 

 of herbs to near the hole. Darwin mentions in 

 The Descent of Man the case of two Roman snails, 

 one sickly and the other vigorous, which were 

 placed in an ill-provided garden. The vigorous one 

 went over the wall into the next garden, where 

 food was abundant. It was absent for twenty-four 

 hours, but when suspicion was growing strong that 

 it had deserted its companion, it returned, and after 

 a short time both disappeared over the wall. That 

 the explorer was able to tell the invalid of the 

 El Dorado over the steep mountains is very im- 

 probable, but the return to the starting-point is 

 quite in line with other observations. It is likely 

 enough that the scent of the slimy trail may assist 

 in the way-finding, though it does not seem certain 

 where the sense of smell has its seat in the common 

 snail. But apart from evidence of " homing " 



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