PSYCHOLOGY 261 



(c} Birds, which are considered under the three divisions of 

 their psychical activity (consciousness of an external world, 

 feeling, will, action), and also in another classification according 

 to their natural degrees of water-, land- and air-birds. 



(d) Mammals also classified according to perception, feeling 

 and will. 



Cams l carefully traced out the gradations in the psychical 

 functions of animals, but as he held them entirely distinct from 

 those of man, so he left completely unobserved the natural 

 development of the animal mind from the lower forms to the 

 higher. 



The first to formulate deliberately and logically a psychic 

 stem-evolution identical with the phylogenetic development of 

 all animals up to man was Haeckel. He recognised no absolute 

 psychological boundary between animals and man, no special 

 psychical functions as the sole prerogative of man. From the 

 monistic standpoint he maintained a complete psychological 

 identity for the whole organic world, extending from the pro- 

 tists up to man, based upon perception and movement and 

 intimately bound up with the existence of protoplasm and a 

 definite metabolism. 



The monistic idea of a gradual psychical development which 

 corresponds with the structural evolution from the lower to the 

 higher forms looms large in modern natural philosophy. One 

 of the ablest protagonists of the theory of descent, Prof. Klaatsch 

 of Heidelberg, does not hesitate to state that precisely as we 

 can claim a stem-history for the skeleton, so experimentally we 

 shall find proof of the phylogeny of the mind and soul. 



The triumph of man over brute creation is probably not the 

 result of any vital difference between man and animal, but 

 only of man's higher intelligence, because many animals have, 

 as regards their brain-development, arrived at the third stage. 



Waitz expresses the same view ; man, he says, rises 

 superior to animals by the force of his original ideas, and by 

 his capacity for adequately giving expression to them. Accord- 

 ing to Waitz, the natural requirements of human life are more 

 difficult to satisfy than those of animals. But this constraint to 

 satisfy his daily needs, his erect gait and his hand, are not the 

 1 Vienna, Braumuller, 1866. 



