FRAGMENTS OF SCIENCE. 



285 



has sufficed for the particular purposes 

 of the physicist. Of course, only a little 

 corner of the universe has been ex- 

 plored, but in the study of non-living 

 matter we have come to no impassable 

 gulfs, no chasms across which we can 

 not throw bridges of hypothesis. Does 

 the method equally suffice when it is 

 applied to living matter? Can we give 

 a purely physical account of such mat- 

 ter? Do we make any attempt to apply 

 the physical method to describe and ex- 

 plain those motions of matter which 

 on the psychical view we term volun- 

 tary? In practice the strictest physi- 

 cist abandons the physical view, and re- 

 places it by the psychical. He admits 

 the study of purpose as well as the 

 study of motion, and has to confess that 

 here the physical method of prediction 

 fails. 



Honors to Sullivant and Lesque- 

 reux. — " Sullivant day," August 22d, 

 was devoted in the American Associa- 

 tion to the commemoration of the lives 

 and works of William S. Sullivant and 

 C. Leo Lesquereux, botanists, the former 

 distinguished for his studies in the 

 mosses and the latter for his researches 

 in paleobotany, both of whom lived and 

 did the work by which they became fa- 

 mous in Columbus, Ohio. Sullivant was 

 born and passed the whole of his life in 

 Columbus. Lesquereux, a Swiss by birth, 

 lived in Columbus during many of his 

 most fruitful years, and worked along- 

 side of Sullivant. A considerable num- 

 ber of objects associated with the two 

 botanists were on exhibition — rare bo- 

 tanical specimens, charts and pictures 

 connected with their labors, and com- 

 plete sets of their published works — and 

 excellent and highly prized portraits of 

 them were shown. The families of both 

 were represented ' by the presence of 

 daughters and granddaughters, among 

 whom was Miss Arhart, a granddaugh- 

 ter of Lesquereux, who was associated 

 with him in part of his work, and made 

 most of the drawings for his later books. 

 Prof. C. R. Barnes presided over the 

 exercises. Prof. W. A. Kellerman read 

 a tribute to Sullivant from Dr. Gray's 

 supplement to the leones. Mrs. Brit- 

 ton gave a short review of the species 

 named from Sullivant (including twelve 

 North American mosses). Professor 

 Barnes read a tribute to Lesquereux, 



taken from the Botanical Gazette. Re- 

 marks were made and papers read on the 

 Progress in the study of the Hepatica, 

 by Prof. L. M. Underwood; the Moss 

 Flora of Alabama, by Dr. Charles Mohr 

 (read by Professor Earle) ; the History 

 of the Study of the Mosses, by Mrs. 

 Britton; the Classification of Certain 

 Mosses, by A. J. Grout; the Study of 

 Lichen Distribution in the Mississippi 

 Valley, by Bruce Fink; and Botanical 

 Teaching in the Secondary Schools, 

 by W. C. Stevens and Ida Clendenin. 

 Among the exhibits, those of twelve 

 species of hepaticse from California, by 

 Prof. F. E. Lloyd; forty- five photo- 

 graphs of American students and col- 

 lectors made famous by their work in 

 mosses, by Mrs. Britton and Professor 

 Underwood; and six species of mosses 

 discovered and collected originally by 

 Sullivant and Lesquereux near Colum- 

 bus, deserve special mention. 



Rate of Evolutionary Variation 

 in the Past. — IMr. Adam Sedgwick, 

 speaking, in his address at the British 

 Association, of variation, selection, and 

 heredity, having raised the question 

 whether the variability of organisms 

 has ever been different from what it is 

 now, answered it in the affirmative, be- 

 cause it would be absurd to suppose 

 that organisms would remain constant 

 in this respect while they have under- 

 gone alteration in all their other prop- 

 erties. According to the Darwinian the- 

 ory of evolution, one of the most impor- 

 tant factors in determining the modifi- 

 cation of organisms has been natural 

 selection. It acts by presenting cer- 

 tain favorable variations, and allo^^^ng 

 others less favorable to be killed off in 

 the struggle for existence. It will thus 

 come about that certain variations will 

 be gradually eliminated, while the vari- 

 ations of the selected organisms will 

 themselves be submitted to selection, 

 and certain of these will in their turn 

 be eliminated. In this way a group 

 of organisms becomes more and more 

 closely adapted to the surroundings. 

 It would thus appear that the result of 

 continued selection is to diminish the 

 variability of a species. Hence, as selec- 

 tion has been going on all the while, 

 variation must have been much greater 

 in past times than it is now. Follow- 

 ing out this train of reasoning, we are 



