342 MENTAL EVOLUTION IN ANIMALS. 



I shall now proceed, as briefly as possible, to render the 

 evidence which has induced me to ascribe each of the above- 

 named emotions to animals, and remembering that I have in 

 each case written the emotion npon the diagram at the level 

 of mental evolution where I have found the earliest evidence 

 of its occurrence, it follows that in the majority of cases the 

 emotion is present in the higher levels of mental evolution 

 in a more highly-developed form. 



It will be observed that in the diagram I represent the 

 Emotions as a class to take their origin from the growing 

 structure of mind at the same level as that at which the 

 faculty of Perception takes its origin. I do this because I 

 think that as soon as an animal or a young child is able to 

 perceive its sensations, it must be able to perceive pleasures 

 and pains ; hence, when the antecedents of a painful percep- 

 tion recur in consciousness, the animal or child must anticipate 

 the recurrence of that perception — must suffer an ideal 

 representation of the pains, and such suffering is Fear. And 

 that, as a matter of fact, Fear of this low or vague order is 

 manifested at about the second or third week of infancy, is 

 the general opinion of those who have most carefully 

 observed the development of infant psychology.* To specify 

 the class in the animal kingdom where a true emotion of 

 Fear first arises is clearly a more difficult matter, and indeed 

 it is impossible to do so in the absence of any definite know- 

 ledge as to the class in which Perception first arises. But while, 

 as previously explained, I am not able to say whether or not 

 the Coelenterata, and still less the Echinodermata, are able to 

 perceive their sensations, I think the evidence becomes very 

 strong in the case of insect Larvse and Worms. And that both 

 the one and the other manifest striking symptoms of alarm 

 in the presence of danger may be easily shown. For instance, 

 a few months ago I had an opportunity of observing the 

 habits of the processional caterpillar mentioned in " Animal 

 Intelligence."t Wishing to ascertain whether I could artifi- 



* See Preyer, loe. cit. 



X Pp. 238-40. It will be seen on referring to this passage that De 

 Villiers' account differs materially from that of Mr. Davis. For he says that, 

 on removing one of the chain of caterpillars, the whole chain stopped imme- 

 diately with one consent, like a single organism. Mr. Davis on the other 

 hand said that the information was communicated from caterpillar to cater- 

 pillar at the rate of somewhat less than a second per caterpillar. On repeat- 

 ing this observation a great number of times, I could obtain no corroboration 

 at all of De Villiers' statement, while I found that of Mr. Davis to be correct 



