I 



PROGRESS OF PSYCHOLOGY. 455 



The history of psycho-physics should give prom- 

 inence to Gustav Fechner who invented (1860) the 

 term (Psychophysik) and first spoke of " physiologi- 

 cal psychology," who was also mainly concerned with 

 a vindication and elaboration of " Weber's Law " 

 (as he called it) ; and to Helmholtz, who measured 

 the velocity of nerve-messages (1851), supplied a 

 provisional physiological basis for the interpreta- 

 tion of visual and auditory sensations, and stood firm 

 by Miiller's conclusion that our senses afford us only 

 symbols of the outer world. Mention should also 

 be made of two general works which had a strong 

 influence: Hermann Lotze's Medicimsche Psychol- 

 ogie, oder Physiologie der Seele (1852) and Herbert 

 Spencer's Principles of Psychology (1855). Dur- 

 ing the last twenty-five years the most prominent 

 figure in Psycho-physics has been Wilhelm Wundt. 

 Among those who have followed him or have struck 

 out on independent lines we may note: — Baldwin; 

 Bethe; Ebbinghaus; James; Pierre Janet; Kraepe- 

 lin; Ladd; Lange; Lipps; Loeb; Lloyd Morgan; 

 Miinsterberg ; Ribot ; Titchener. 



The utility of the experimental method is (1) in 

 giving point and precision to introspection, (2) in 

 making a certain amount of measurement possible, 

 and (3) in correlating definite variations in mental 

 process with definite variations in the conditions. 



COMPARATIVE PSYCHOLOGY. 



A new day began in Physiology when Johannes 

 Miiller made it a comparative study; and although 

 the study of the animal mind has not, as yet, yielded 

 such rich results to the psychology of man as might 



