August 28, 1914] 



SCIENCE 



293 



the naturalist — and it is to him that I am 

 especially addressing myself to-day — these 

 things are chiefly significant as relating 

 to the history of organic beings — the theory 

 of evolution, to use our modern name. 

 They have, as I shall endeavor to show in 

 my second address to be given in Sydney, 

 an immediate reference to the conduct of 

 human society. 



I suppose that every one is familiar in 

 outline with the theory of the origin of spe- 

 cies which Darwin promulgated. Through 

 the last fifty years this theme of the natu- 

 ral selection of favored races has been 

 developed and expounded in writings in- 

 numerable. Favored races certainly can 

 replace others. The argument is sound, 

 but we are doubtful of its value. For us 

 that debate stands adjourned. We go to 

 Darwin for his incomparable collection of 

 facts. We would fain emulate his scholar- 

 ship, his width and his power of exposition, 

 but to us he speaks no more with philo- 

 sophical authority. We read his scheme of 

 evolution as we would those of Lucretius 

 or of Lamarck, delighting in their simplic- 

 ity and their courage. The practical and 

 experimental study of variation and hered- 

 ity has not merely opened a new field; it 

 has given a new point of view and new 

 standards of criticism. Naturalists may 

 still be found expounding teleological 

 systems^ which would have delighted Dr. 



5 I take the following from the abstract of a re- 

 cent Croonian Lecture ' ' On the Origin of Mam- 

 mals" delivered to the Eoyal Society: "In Upper 

 Triassie times the larger Cynodonts preyed upon 

 the large Anomodont, Kannemeyeria, and carried 

 on their existence so long as these Anomodonts 

 survived, but died out with them about the end of 

 the Trias or in Ehstie times. The small Cyno- 

 donts, having neither small Anomodonts nor small 

 Cotylosaurs to feed on, were forced to hunt the 

 very active long-limbed Thecodonts. The greatly 

 increased activity brought about that series of 

 changes which formed the mammals — ^the flexible 

 skin with hair, the four-chambered heart and 



Pangloss himself, but at the present time 

 few are misled. The student of genetics 

 knows that the time for the development of 

 theory is not yet. He would rather stick 

 to the seed-pan and the incubator. 



In face of what we now know of the dis- 

 tribution of variability in nature the scope 

 claimed for natural selection in determin- 

 ing the fixity of species must be greatly 

 reduced. The doctrine of the survival of 

 the fittest is undeniable so long as it is 

 applied to the organism as a whole, but to 

 attempt by this principle to find value in 

 all definiteness of parts and functions, and 

 in the name of science to see fitness every- 

 where is mere eighteenth-century optimism. 

 Yet it was in application to the parts, to 

 the details of specific difference, to the 

 spots on the peacock's tail, to the coloring 

 of an orchid flower, and hosts of such ex- 

 amples, that the potency of natural selec- 

 tion was urged with the strongest emphasis. 

 Shorn of these pretensions the doctrine of 

 the survival of favored races is a truism, 

 helping scarcely at all to account for the 

 diversity of species. Tolerance plays al- 

 most as considerable a part. By these ad- 

 missions almost the last shred of that teleo- 

 logical fustian with which Victorian philos- 

 ophy loved to clothe the theory of evolution 

 is destroyed. Those who would proclaim 

 that whatever is is right will be wise hence- 

 forth to base this faith frankly on the 

 impregnable rock of superstition and to 

 abstain from direct appeals to natural fact. 



My predecessor said last year that in 

 physics the age is one of rapid progress and 

 profound scepticism. In at least as high 



warm blood, the loose jaw with teeth for mastica- 

 tion, an increased development of tactile sensation 

 and a great increase of cerebrum. Not improbably 

 the attacks of the newly-evolved Cynodont or mam- 

 malian type brought about a corresponding evolu- 

 tion in the Pseudosuchian Thecodonts which ulti- 

 mately resulted in the formation of Dinosaurs and 

 Birds. ' ' Broom, E., Froo. Boy. Soc. B., 87, p. 88. 



