260 THE HUMAN SPECIES 



blances in the psychic functions of the higher animals. " Man 

 and the higher animals, especially the primates, have some few 

 instincts in common. All have the same senses, intuitions and 

 sensations, similar passions, affections and emotions, even the 

 more complex ones such as jealousy, suspicion, emulation, 

 gratitude and magnanimity ; they practise deceit and are 

 revengeful ; they are sometimes susceptible to ridicule and 

 even have a sense of humour ; they feel wonder and curiosity ; 

 they possess the same faculties of imitation, attention, delibera- 

 tion, choice, memory, imagination, the association of ideas 

 and reason though in very different degrees. The individuals 

 of the same species graduate in intellect from absolute imbecil- 

 ity to high excellence. They are also liable to insanity, though 

 far less often than in the case of man." : 



Darwin alluded to the general similarity between the mind 

 of man and animals without, however, formulating a stem-evolu- 

 tion, a phylogenetic development of the mind. It is a very 

 interesting fact that one of the great opponents of Darwinism 

 sketched out such a stem-evolution. Carus, in his Comparative 

 Psychology, or History of the Mind in the Animal Kingdom, gave 

 a schematic survey in tabular form of two natural series, of 

 which the one dealt with the evolution of the human mind, while 

 the other in a very similar scheme of development gave the 

 proofs of innumerable gradations in the infinite multiplicity of 

 animal souls without arriving at the final conclusion. 



The first class of Carus includes the protists and all the 

 lower forms without differentiated nerves. The second class 

 consists of species which have no brain : 



(a) Those with a problematical or non-central nervous 

 system (polyps, acrania, higher radiates, acraniate molluscs, 

 and lower articulates). 



(If) Those with a central nervous system (higher molluscs, 

 higher articulates). 



In the third class are the species with a tripartite brain (fore-, 

 mid- and hind- brain), and more or less definite cranium, the 

 type of perfection and the symbol of psychical development : 



(a) Fishes. 



() Amphibia and reptiles. 



1 Descent of Man, vol. i. (Murray, 1888), p. 120. 



