PROGRESS OF PSYCHOLOGY. 471 



(a) He may utilise past mental products, — the 

 words and structure of language in which thought 

 is embodied, the beliefs and customs of races, their 

 works of art, and so on. 



(b) Valuable data are also obtainable by the study 

 of children, — a line of investigation practically be- 

 gun by Preyer, and at present well represented by 

 Prof. Mark Baldwin * and Stanley Hall. 



(c) From experimental work — in which the stages 

 of a mental product can sometimes be detected ; and 

 from comparisons of normal subjects with the blind 

 or the deaf, another set of data are obtainable. 



(d) Lastly, some help has been forthcoming from 

 the studies of those who, like Komanes and Lloyd 

 Morgan, have paid particular attention to the animal 

 mind. 



CONCLUSION. 



We have, in this chapter, briefly illustrated four 

 steps of recent progress in psychology: — (a) the 

 fuller recognition of the correlations between body 

 and mind, (b) the rapidly increasing habit of resort- 

 ing to experiment, (c) the broadening of the science 

 on comparative lines, and (d) the endeavour to look 

 at all the facts from a genealogical or evolutionary 

 standpoint. 



We are reminded that there are other important 

 steps, — the beginning of a social psychology (Tarde, 

 Baldwin, Royce, Le Bon) ; the beginning of a care- 

 ful psychology of sex (Havelock Ellis) ; the develop- 

 ment of practical psychology in reference to educa- 

 tion (James, Lloyd Morgan, and many others) ; the 



♦ Mental Development in the Child and the Race, 2 vols. 



