152 MENTAL EVOLUTION IN MAN. 



speech to have had a natural mode of genesis, it is, in 

 my opinion, perfectly certain that its origin and develop- 

 ment must have been greatly assisted by gesture. In sub- 

 sequent chapters I will adduce direct evidence upon this 

 head. At present I wish to draw attention to another point. 

 This is, that although gesture psychologically precedes speech, 

 when once articulate sounds have been devised for the ex- 

 pression of ideas, the faculty of using these articulate sounds 

 as signs of their corresponding ideas does not involve the 

 presence of a higher psychological development than does 

 the faculty of using tones and gestures for the conveyance of 

 similar ideas. 



As already shown, it is a matter of observable fact that 

 the only animals which are able to articulate are able to 

 employ nouns, adjectives, and verbs, as expressive of concrete 

 ideas ; while animals which are not able to articulate similarly 

 employ tones, and in many cases are able to understand 

 words. Therefore, it is a matter of observable fact that the 

 psychological level required for using tones as vocal gestures, 

 understanding words as expressive of simple ideas, and even 

 uttering words with a correct appreciation of their meaning, 

 is a level not higher than that which obtains in some existing 

 animals. 



If we turn from animals to man, we find the same truth 

 exemplified. For in the descending grade of human intelli- 

 gence as exhibited by idiots, we see that while the use of 

 simple gestures as signs occurs in idiots somewhat too low in 

 the scale to utter any articulate words, nevertheless the 

 interval between such an idiot and one capable of uttering 

 the simplest words is a short interval. Again, in the ascend- 

 ing grade of human intelligence, as exhibited by the growing 

 child, we find the same observation to apply ; although, on 

 account of some children requiring a longer time than others 

 to develop the mechanique of articulation, we might by con- 

 sidering their cases alone over-estimate the psychological 

 interval which separates gesticulation from speech. * 



* It will be remembered that in a previous chapter I argued the impossibility 



