THE SPEECH OF MONKEYS. 203 



chemical world one element will select another 

 with which it will combine, while to other ele- 

 ments it shows a great aversion. When one 

 chemical element selects another and combines 

 with it, we call this chemical affinity. The ul- 

 timate force which causes this affinity is one of 

 the unknown facts concerning matter, but it is 

 possible that such affinities and aversions con- 

 stitute the basis upon which rest the selections 

 and aversions of plants and animals. But as we 

 rise in the scale, the combinations of matter be- 

 come more complex and the functions of each 

 part more specific. It is possible, when we be- 

 come more familiar with the forces of nature, 

 that we will find that affinity and repulsion are 

 but the positive and negative poles of the forces 

 which act on matter, and that chemical, vegetable, 

 and animal activity are based upon the same 

 fundamental causes, and that speech, which is 

 only one form of expression, is the highest prod- 

 uct of such an ultimate force, but in all condi- 

 tions of matter such forces, either positive or 

 negative, are the ultimate motives of expression. 

 As chemical formulas differ from each other 

 without losing the identity of their elements 

 which constitute them, so animal organisms and 



