ANT COMMUNITIES 



some signal from nature, some potent impulse or con- 

 dition. 



Setting aside, then, the completed cycle of maturity 

 as the sole cause of this remarkable assembly, it is in- 

 teresting and not improbable to suppose that a wave of 

 sympathetic excitement issuing from a few nests may 

 have infected all the surrounding section until, by a 

 common impulse, the entire emmet population of the 

 mountain-side was astir with the fever of flight. We 

 know how, in human societies, neighboring families, 

 towns, and cities are apt to be seized almost simultane- 

 ously with a political or patriotic or religious fervor, or 

 revival, that spreads with a swiftness and complete- 

 ness that are so remarkable as to appear to many quite 

 beyond known causes. With equal celerity and uni- 

 versality, and equal mystery of psychological cause, 

 will panics spread among armies and communities of 

 our race. 



Psychic contagions are not confined to men. The 

 animal world, in some of its races, at least, is subject 

 thereto ; and to these, in some measure, we may attribute 

 the impulse that seizes at once the myriads of winged 

 ants, and sets them forth together. This impulse must 

 be felt by the workers also, the rulers of the communes, 

 if indeed it does not originate with them: for their de- 

 pendents are not always willing exiles from the favorel 

 precincts of the home nest. I have seen them turning 

 back at first with manifest reluctance, and seeking to 

 enter the city gates against the ungentle persuasion of 

 the workers' sharp mandibles. It requires such dis- 

 cipline and the allied mighty force of a natural instinct 

 to banish them from their sheltered life of ease in their 

 happy native homes. 



178 



