10 INTRODUCTION. 



talented contemporary, Herder, grasp the nature of animals, 

 whom, in his " Thoughts for a Philosophy of Human His- 

 tory," he calls with keen insight " the elder brethren of 

 men." Brain development and erect position have made 

 men into men ; yet in the animal-kingdom we see the rudi- 

 ments of all the higher moral and intellectual faculties of 

 man, such as reason, speech, art, freedom, etc. 



With this last declaration, Herder approaches very nearly 

 the standpoint of modern thought, which no longer recog- 

 nises in animals a difference of kind, but only a difference 

 of degree, and which sees the principle of intelligence 

 developing through one endless and unbroken series, 

 gradually and slowly, by way of countless acquisitions, 

 inheritances, and transmissions, from its lowest stage to its 

 highest. " The principle exists without doubt," says the 

 anti-materialist, Agassiz, on this point (" Treatise on 

 Natural History," U.S.A.), " and whether it be called 

 soul, reason, or instinct, it displays in the whole series of 

 organised beings a succession of closely interwoven pha3- 

 nomena." According to Huxley, the admirable English 

 naturalist ("Natural History Review, 1861"), no impartial 

 judge can doubt that the roots of all those great capabilities, 

 which give to man his immeasurable superiority over all 

 other living things, can be traced deep into the animal 

 world. 



