156 THE EVOL UTION OF LA NG UA GE. 



animals, for the most part timid and defenceless as 

 individuals, have survived to occupy in untold multi- 

 tudes the highest places in Nature. 



The success of the co-operative principle, however, 

 depends upon one condition : the members of the herd 

 must be able to communicate with one another. It 

 matters not how acute the senses of each animal may 

 be, the strength of the column depends on the power 

 to transmit from one to another what impressions 

 each may receive at any moment from without. 

 Without this power the sociality of the herd is stulti- 

 fied; the army, having no signalling department, is 

 powerless as an army. But if any member of the 

 herd is able by motion of head or foot or neck or ear, 

 by any sign or by any sound, to pass on the news that 

 there is danger near, each instantly enters into posses- 

 sion of the faculties of the whole. Each has a hun- 

 dred eyes, noses, ears. Each has quarter of a mile 

 of nerves. Thus numbers are strength only when 

 strength is coupled with some power of intercom- 

 munication by signs. If one herd develops this sig- 

 nalling system and another does not, its chances of 

 survival will be greater. The less equipped herds will 

 be slowly decimated and driven to the wall; and 

 those which survive to propagate their kind will be 

 those whose signal-service is most efficient and com- 

 plete. Hence the Evolution of the signal-system. 

 Under the influence of Natural Selection its progress 

 was inevitable. New circumstances and relations 

 would in time arise, calling for additions, vocal, visi- 

 ble, audible, to the sign-vocabulary. And as time 

 went on each set of animals would acquire a definite 

 signal-service of its own, elementary to the last 



