30 ANTS AND SOME OTHER INSECTS. 



arouse one another into activity in certain sequences, there is also 

 a time interval, filled out by internal, dynamic brain-processes as 

 in the case of the will. Hence these are not pure reflexes. They 

 may for a time suffer interruption and then be again continued. 

 But their operation is brought about in great measure by a con- 

 catenation of complicated reflexes which follow one another in a 

 compulsory order. On this account the term automatism or in- 

 stinct is justifiable. 



If we are to speak of will in the narrower sense, we must be 

 able to establish the existence of individual decisions, which can be 

 directed according to circumstances, i. e., are modifiable, and may, 

 for a certain period, remain dormant in the brain to be still per- 

 formed notwithstanding. Such volition may be very different from 

 the complex volition of man, which consists of the resultants of 

 prodigiously manifold components that have been long preparing 

 and combining. The ants exhibit positive and negative volitional 

 phenomena, which cannot be mistaken. The ants of the genus 

 Formica Linn are particularly brilliant in this respect, and they 

 also illustrate the individual psychical activities most clearly. The 

 above-mentioned migrations from nest to nest show very beauti- 

 fully the individual plans of single workers carried out with great 

 tenacity. For hours at a time an ant may try to overcome a multi- 

 tude of difficulties for the purpose of attaining an aim which she 

 has set herself. This aim is not accurately prescribed by instinct, 

 as the insect may be confronted with several possibilities, so that 

 it often happens that two ants may be working in opposition to 

 each other. This looks like stupidity to the superficial observer. 

 But it is just here that the ant's plasticity reveals itself. For a 

 time the two little animals interfere with each other, but finally 

 they notice the fact, and one of them gives in, goes away, or assists 

 the other. 



These conditions are best observed during the building of nests 

 or roads, e. g., in the horse-ant {Formica rufa) and still better in 

 P. pratensis. It is necessary, however, to follow the behavior of a 

 few ants for hours, if one would have a clear conception of this 

 matter, and for this much patience and much time are necessary. 



