CONGRESS OF ARTS AND SCIENCE. 27 



For De Vries has been able to see with his own eves the actual evolution 

 of several new plant forms possessing the characters of true species, 

 and lias accumulated a vast amount of exact evidence, in support of the 

 theory that new species arise suddenly from marked variations of the 

 discontinuous sort, called ' mutations/ rather than by the gradual 

 accumulation, through successive generations, of slight differences due 

 to the ordinary "' fluctuating variation,' as Darwin had supposed. 



This mutation theory of De Vries was discussed by its author 

 before the section, while Whitman, after a general historical survey 

 of his subject, discussed the interesting results obtained from a pro- 

 longed and controlled study of the evolution of color-pattern in the 

 feathers of pigeons which he has bred for many years. Here the 

 changes seem gradual, yet stable. As to the degree to which the two 

 sets of results conflict, it would be premature to pronounce judgment. 



Anthropologists were enabled to hear in their sectional meetings 

 Manouvrier, of Paris, perhaps now the foremost name in physical an- 

 thropology; Seler, of Berlin, in American archeology; Haddon, of 

 Cambridge, in ethnology. 



The temptation must be resisted to report in detail the psycho- 

 logical sectional meetings. Denmark's ablest psychologist and Eng- 

 land's, both eminent also in philosophy, discussed the relations and 

 problems of general psychology with characteristic breadth and pene- 

 tration. It was indeed a notable occasion when Hoeffding and Ward 

 were introduced by Eoyce. 



In another section Lloyd Morgan discussed the relations of the 

 animal psychology which he may be said to have shaped for a band 

 of younger workers who were in large part present to hear him, while 

 Miss Mary W. Calkins, professor in Wellesley College, presented in 

 excellent form a discriminating statement of the problems of genetic 

 and comparative psychology in the large. As those addresses had been 

 preceded by some well-chosen remarks by the chairman, Professor E. 

 C. Sanford, who has directed important experimental work in com- 

 parative psychology, so they were followed by short papers of general 

 methodological interest — one by the lamented Dr. C. L. Herrick, late 

 editor of the Journal of Comparative Neurology and Psychology, read 

 by Professor C Judson Herrick, in which the dynamic or functional 

 standpoint was emphasized; another by Dr. John B. Watson, of 

 Chicago, urging the desirability of combining neurological studies, 

 both experimental and histological, with systematic observations of 

 animal behavior. Some matters of method, involving such questions 

 as the criterion of consciousness, were broached in another short 

 address, and there followed an interesting discussion which led to a 

 pleasant lunch party. 



The fascinating but baffling questions of abnormal psychology 

 were discussed in another section by Dr. Pierre Janet, of the Sal- 

 petriere, world-famed psychiatrist and psychologist, eminent as a 



