Page:Popular Science Monthly Volume 66.djvu/31

Rh 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 has 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 prolonged 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 anthropology; Seler, of Berlin, in American archeology; Haddon, of Cambridge, in ethnology.

The temptation must be resisted to report in detail the psychological sectional meetings. Denmark's ablest psychologist and England's, both eminent also in philosophy, discussed the relations and problems of general psychology with characteristic breadth and penetration. It was indeed a notable occasion when Hoeffding and Ward were introduced by Royce.

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 comparative 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 Salpêtrière, world-famed psychiatrist and psychologist, eminent as a