METHOD OF STUDY. 7 



extent of the mental operations of the lower animals are 

 superabundant, it is a self-evident corollary that the student 

 who professes or proposes to devote himself to investigations 

 in comparative psychology should bring to his task at least 

 the following qualifications : 



1. He may have to unlearn much that he has already 

 learned for instance, as regards the supposed necessary con- 

 nection of mind with brain or nervous system and unlearning 

 is always a difficult matter. * Learn of me,' said Luther, 

 ' how hard it is to unlearn the errors which the whole world 

 confirms by its example, and which by long use have become 

 to us as a second nature.' 



2. He must be prepared to change, or at least enlarge, 

 his conceptions of the nature and range of mind. 



3. He should re-study carefully certain phenomena of the 

 human mind, more especially the inter-relations of con- 

 sciousness and unconsciousness, and the whole subject of 

 reflex or automatic cerebro-spinal action. 



4. He should further consider in detail the mental phe- 

 nomena of acephalous animals or infants ; the attributes of 

 the spinal cord and of the different classes of nerves when 

 disconnected from or unassociated with brain. 



5. His study of the human mind must not be confined to 

 its highest manifestations or as it has been developed by 

 generations of high culture in the most intelligent of 

 civilised peoples, but it must embrace its lowest manifesta- 

 tions its stages of non-development, non-cultivation, de- 

 generation, retrogression ; in all conditions of disease, 

 moreover, as well as in health. Hence his field of enquiry 

 must include man in all the different stages of the social 

 scale, the genesis and progress or development of mind in 

 the infant, civilised and savage, with the morbid psychical 

 phenomena of the idiot and lunatic. 



6. He should enquire further whether the bases of mind 

 are not to be found in the vegetable kingdom in the form, for 

 instance, of purposive action; l what are the bases of mind in 

 plants and the lower animals; what is consciousness, and 



1 I have inaugurated enquiry in this direction in a paper mentioned in 

 the Bibliography. 



