570 



SCIENCE. 



[N. S. Vol. VII. No. 173. 



said, on his return from Europe, occupy a chair 

 in the newly-established School of Pedagogy in 

 Cornell University, devoting himself chiefly to 

 problems of child-study. 



At the meeting of the Board of Regents of 

 the University of California on April 12th Mrs. 

 Phoebe Hearst offered to construct and equip at 

 her expense a building for the College of Mines. 



McGiLL University has suffered severe losses 

 in the resignation of Professor Hugh L. Callen- 

 dar, of the chair of physics, and Professor C. 

 A. Carus-Wilson, of the chair of electrical 

 engineering. Professor Callendar has been 

 appointed to the chair of physics in University 

 College, London, vacated by the resignation of 

 Professor Carey Foster. 



The summer session of the University of Ne- 

 braska opens on June 6th and closes July 16th. 

 It is to take the place of the University Summer 

 School, hitherto maintained for from two to four 

 weeks each year. Regular University work 

 will be offered in eighteen departments and 

 special work in six or seven more. It is the ex- 

 pectation of the University authorities ulti- 

 mately to develop the summer session so as to 

 afford opportunities for vacation work along 

 nearly all lines of University study. The 

 sciences now offered are botany, chemistry, 

 entomology, geology, physics and zoology. 



DISCUSSION AND CORRESPONDENCE. 



ISOLATION AND SELECTION. 



To THE Editor of Science : "Will you per- 

 mit me to use youj; pages for protesting against 

 the indiscriminate use of the word ' Selection ' 

 by writers on Organic Evolution. Selection 

 means the act of picking out certain objects 

 from a number of others, and it implies that 

 these objects are chosen for some reason or other. 

 Now Selection, by itself, can never originate a 

 new variety or a new species. To do this it 

 must always act in conjunction with the isola- 

 lation of the selected individuals. 



'Artificial Selection,' by which breeders form 

 new races of domesticated animals, consists of 

 two distinct processes. The breeder first selects 

 his animals and then isolates them from those 

 which have not been selected. It is isolation 

 of the individuals which produces the new race; 



selection merely determines the direction che 

 new race is to take. On the other hand. Isola- 

 tion is capable of originating new species with- 

 out the cooperation of Selection. For, if a few 

 individuals of a species become isolated from 

 the others by some physical agency, such as a 

 flood, a drought or a hurricane, and happen to 

 have some peculiarity or variation different from 

 the average of the species, that variation will 

 now have a special chance of being propagated 

 and probably intensified, although the original 

 parents were not selected in any way. The one 

 factor common to all cases of organic evolution 

 is Isolation, and consequently it must be con- 

 sidered as the most important factor. 



I have summarized the different ways in 

 which Isolation can be brought about in a paper 

 in Natural Science for October, 1897, to which I 

 may be allowed to refer any of your readers 

 who are interested in the matter. Selection 

 implies the a'ction of a Selector outside of the 

 individuals which are selected, whether that 

 Selector be, or be not, conscious of what he is 

 doing ; this is the Artificial Selection of Darwin. 

 Natural Selection is not truly selection, for the 

 individuals can hardly be said to select them- 

 selves by their superior strength, cunning, or 

 what not. Still the term has become so firmly 

 established that it can well be allowed to pass, 

 if used only in Darwin's sense of advantage 

 gained in the struggle for existence, either by 

 the individual or by the species. It is, cer- 

 tainly, quite as good a term as Organic Selec- 

 tion, and has the advantage of having been 

 proposed by the founder of the doctrine of 

 evolution. 



I quite agree with Professor Mark Baldwin 

 and others that Determinate Evolution is the 

 only explanation of the main facts of organic 

 progress. But alongside of this Determinate 

 Evolution a large amount of Indeterminate 

 Evolution has also been going on. For ex- 

 ample, although Humming Birds and Diatoms, 

 as groups, are the product of Determinate Evo- 

 lution, I cannot believe that all the specific 

 characters of the various Humming Birds, or 

 the specific and generic characters of the various 

 Diatoms, are due to the same agency, for they 

 show no definite tendency in any direction, but 

 merely variety. 



