246 



SCIENCE. 



[N. S. Vol. VIII. No. 191. 



one, of the acceptance of the theory of 

 descent on working zoologists is to broaden 

 their minds. Collectors of insects and shells, 

 or of birds and mammals, instead of being 

 content simply to acquire specimens for 

 their cabinets, are led to look during their 

 field excursions for examples of protective 

 mimicry, or to notice facts bearing on the 

 immediate cause of variation. Instead of 

 a single pair of specimens, it is now realized 

 that hundreds and even thousands collected 

 from stations and habitats wide apart are 

 none too many for the study of variation as 

 now pursued. 



The race of ' species grinders ' is diminish- 

 ing, and the study of geographical distribu- 

 tion, based as it is on past geographical 

 changes and extinctions, is now discussed 

 in a far more philosophical way than in the 

 past. The most special results of work in 

 cytologj^ and morphology are now affording 

 material for broad work in phylogeny and 

 heredity. 



On the other hand, it must be confessed 

 that, as the result of the acceptance of evo- 

 lutionary views, our literature is at times 

 flooded with more or less unsound hypothe- 

 ses, some tedious verbiage and long-winded, 

 aerial discussions, based rather on assump- 

 tions than on facts. But on the whole, per- 

 haps, this is a healthy sign. Too free, 

 exuberant growths will be in the long run 

 lopped off by criticism. 



One tendency should be avoided by 

 younger students, that of too early special- 

 ization, and of empirical work without a 

 broad survey of the whole field. In some 

 cases our histologists and morphologists 

 rise little above the intellectual level of 

 species describers. Expert in the use of 

 the microtome and of reagents, they appear 

 to have but little more general scientific or 

 literary culture than high-class mechanics. 

 The chief antidote, however, to the danger 

 of narrowness is the lessons derived from 

 evolutionary thought and principles. 



Finally, as a proof of the value of evolu- 

 tionary ideas to the present generation, let 

 us suppose for a moment, if it were con- 

 ceivable, that they should be blotted out. 

 The result, it is safe to say, would be 

 equivalent to the loss of a sense. 



It is a matter of history that when a new 

 idea or pi-inciple, or a new movement in 

 philosophy or religion, arises it at first de- 

 velops along the line of least resistance; 

 the leaders of the new thought acquire 

 many followers or disciples. Soon the lat- 

 ter outstrip their teachers, and go to greater 

 extremes ; modifications of the original 

 simple condition or theory occur, and as 

 the final i-esult there arise schisms and dif- 

 ferentiations into new sects. This has hap- 

 pened in science, and already we have 

 evolutionists divided into Lamarckians and 

 Darwinians, with a further subdivision of 

 them into ISTeolamarckians and ISTeodar- 

 winians, while the latter are often denom- 

 inated Weismannians. Some prefer to rely 

 on the action of the primary factors of 

 evolution ; others believe that natural selec- 

 tion embraces all the necessary factors, 

 while still others are thoroughly persuaded 

 of its inadequacy. 



The result of this analytical or differ- 

 entiating process will probably be an ulti- 

 mate synthesis, a belief that there is a 

 complex of factors at work. Of these fac- 

 tors those originally indicated by Lamarck, 

 with the supplementary' ones of competition 

 and natural selection bequeathed by Dar- 

 win, are the most essential and indis- 

 pensable, and it is difiicult to see how they 

 can be disjilaced by other views. Mean- 

 while all agree, and it was never more firmly 

 established than at this moment, that there 

 is, and always has been, unceasing energy, 

 movement and variation, a wonderful 

 adaptation and harmony in nature, be- 

 tween living beings and their surroundings. 



The present status of evolution in its dif- 

 ferent phases or attitudes since the time of 



