172 ORGANIC EVOLUTION — MENTAL 



" F. rwfescens, the structure of the animal is such as 

 to render self-feeding physically impossible. Its long 

 and narrow jaws, adapted to pierce the head of an 

 enemy, do not admit of being used for feeding, unless 

 liquid food is poured into them by the mouth of a slave. 

 This fact shows of how ancient an origin the instinct of 

 slave-making must be ; it has altered in an important 

 manner a structure which could not have been so 

 altered prior to the establishment of the instinct in 

 question." — Animal Intelligence, p. 66. 



When we consider that, though our knowledge of ants 

 is yet in its infancy, we have already sufficient informa- 

 tion to warrant us in placing these minute insects above 

 all animals except man — I had almost said civilized 

 man — in regard to their powers of reason, we may be 

 permitted to question whether the habit of slave-making 

 should not be classed as an act of reason rather than one 

 of instinct. The fact that the slaves, in their new 

 homes, so readily adapt themselves to the changed 

 environment, so readily exhibit knowledge and ways 

 of thinking and acting which must be acquired and 

 cannot possibly be instinctive, for the reason that their 

 ancestry can never have been subjected to the influence 

 of a like environment, proves how great a share reason 

 has in all that is mental in them. And since the slaves 

 clearly acquire mental traits which fit them for their 

 duties as servants, it is not unreasonable to suppose that 

 the slave-holders in like manner individually acquire 

 the mental traits which fit them for their functions as 

 masters, i. e. that the slave-holding habit in them is not 

 instinctive but rational. The question is capable, I 

 imagine, of experimental investigation. Should it 

 prove that the slave-making habit is an individually 

 acquired, not an inborn trait, we should then have, in the 

 highly modified structures of F. rtofescens, an example 



