68 MENTAL EVOLUTION IN ANIMALS. 



thesis ; aad, as we shall see, these facts, as I have presented 

 them, are sustained or corroborated by many others drawn 

 from observations on the psychology of animals and children. 

 Again, in the columns devoted to the emotions and faculties 

 of intellect, the results of actual observation predominate over 

 those yielded by speculation ; while in the remaining columns 

 the results tabulated are for the most part due to observa- 

 tion. 



Therefore I submit that if the hypothesis of mental 

 evolution be granted, and if all the matters of observable 

 fact which the diagram serves to express are eliminated, com- 

 paratively little in the way of deductive reasoning is left ; 

 and of this little most follows as necessary consequence from 

 the original hypothesis of mental evolution having taken 

 place. Of course any one who does not already ciccept the 

 theory of evolution in its entirety, may object that I am 

 thus escaping from the charge of speculation only by assum- 

 ing the truth of that which grants me all that I require. To 

 this I answer that as far as the evidence of Mental Evolution, 

 considered as a fact, is open to the charge of being specula- 

 tive, I must leave the objector to lodge his objection against 

 Mr. Darwin's '' Origin of Species " and " Descent of Man." I 

 shall be abundantly satisfied with my own work if, taking 

 the process of Mental Evolution as conceded, I can make it 

 clear that the main outlines of its history may be determined 

 without any considerable amount of speculation, as dis- 

 tinguished from deduction following by way of necessary 

 consequence from the original hypothesis. 



Having thus explained the plan and principles of the 

 diagram, I shall now consider the levels from the lowest as 

 far as the rise of the first branch, i.e., from 1 to 14. After 

 what has already been said in the foregoing chapters on the 

 Physical Basis and Eoot-principles of Mind, our consideration 

 of this part of the diagram need not detain us long. 



Levels 1 to 4 are occupied by Excitability, Protoplasmic 

 Movements, Protoplasmic Organisms, and \h.Q generative 

 elements which have not yet united to start the Embryo of 

 Man. From 4 to 9 we have the levels filled by the rise and 

 progress of the functions Conductility and Discrimination, 

 which by their subsequent union at 9 lay the basis of 

 Xeurility, or the stem of Mind ; in these levels occur the 



