ROMANES ON MEMORY 407 



mind without memory is useful. Romanes himself, by means of a 

 somewhat cruel experiment, afforded clear evidence of the lack of 

 memory in low animals and the usefulness of sensation in its 

 absence. " I am more surprised with my failure in this respect 

 with the higher Crustacea ; for although I have tried similar 

 experiments with them I have never been able to teach them the 

 simplest things. Thus, for instance, I have taken a hermit crab 

 and put it into a tank filled with water, and when he had pro- 

 truded his head from the shell of the whelk in which he was 

 residing, I gently moved towards him a pair of open scissors, and 

 gave him plenty of time to see the glistening object. Then, 

 slowly including the tip of one of his tentacles between the open 

 blades, I suddenly cut off the tip. Of course the animal immedi- 

 ately drew back into the shell, and remained there for a consider- 

 able time. When he again came out I repeated the operation as 

 before, and so on for a great number of times, till all the tentacles 

 had been progressively cut away little by little. Yet the animal 

 never learnt to associate the appearance of the scissors with the 

 effect which always followed it, and so never drew in till the snip 

 had been given. Nevertheless, that memory does occur among 

 the higher Crustacea is proved by an observation quoted in 

 Animal Intelligence (p. 233), concerning a lobster mounting guard 

 upon a heap of shingle beneath which it had previously had hidden 

 some food." 1 



672. That memory is absent or very rudimentary in hermit 

 crabs is proved by the experiment. That the action of the lobster 

 indicates memory is not so certain. 2 Though named in the margin, 

 memory had no place in Romanes' famous diagram which precedes 

 his works on Mental Evolution and which was "intended to represent 

 in one view the whole course of mental evolution," 3 and concerning 

 which he wrote, " I feel confident that the general structure of our 

 knowledge concerning the evolution of mind is now sufficiently 

 coherent to render it highly improbable that this diagrammatic 

 representation of it will, in the future, be altered in any of its main 

 features by any advances that science may be destined to make." 4 

 In his list of the products of intellectual development memory is 

 placed before the primary (i.e. the earliest) instincts. 5 



673. Recent writers make also as little mention of memory as 

 a factor in mental evolution as Darwin. The mental 'plasticity' 



1 Op. cit., pp. 122-3. z See 689. 



3 Mental Evolution in Animals, p. 63. 4 Op. cit., pp. 63-4. 



6 See Romanes' diagram. 



