THE ORIGIN OF THE VOICE 19 



witnessed the incident some hundreds of times. 

 Young frogs {R. teniporarid) sometimes scream 

 when seized by a snake ; and in this case an 

 inherited cry is produced in its full tone by an 

 animal which has never before made use of any 

 vocal power it may possess. 



Among the earlier forms of life the voice was 

 probably of accidental rather than voluntary origin. 

 In the amphibians it may have been originated in 

 the same manner as it is now first used by the 

 newts, and have survived in consequence of an 

 advantage it conferred in battle. Among mammals 

 and birds it may have been inherited from an earlier 

 source ; or in the former it may have been elabor- 

 ated from snorts and grunts, and in the latter the 

 violent actions and rapid breathing incidental to 

 combats in the air may have initiated a power which 

 was afterwards adopted as a means of expressing a 

 threat. Birds of several genera make an audible 

 snapping noise with their bills when they fight ; but 

 the greenfinch, chaffinch, and house-sparrow, under 

 the same conditions, sometimes produce a hoarse 

 kind of note which appears to be due partly to the 

 very rapid striking together of the mandibles, and 

 partly to some guttural sound. This reference to 

 the house-sparrow must be read in connection with 



