106 



SCIENCE. 



[N. S. Vol. XXII. No. 552. 



-has not only not been uniform during geo- 

 logical time, but that it has been exceed- 

 ingly diverse; that those genera, families, 

 orders and classes which have become ex- 

 tinct have, in many cases, declined and 

 perished amid general conditions of phys- 

 ical environment which were evidently 

 quite as favorable to their existence as were 

 those amid which they originated; that 

 certain generic and family forms have sur- 

 vived unchanged through vicissitudes and 

 restrictions of habitation so adverse as to 

 have been again and again apparently more 

 than sufficient for their utter destruction; 

 and that unknown determinate natural 

 causes have acted, sometimes in the de- 

 struction, sometimes in the conservation, 

 and sometimes in the extreme differentia- 

 tion, of typical forms of life, often in seem- 

 ing independence of environing physical 

 conditions. In making application of those 

 facts it will be shown that some theory of 

 the rapid or sudden origination of species 

 is necessary to harmonize them with the 

 past conditions which they reveal. That 

 the theory of the origin of species by nat- 

 ural selection will not harmonize with 

 those facts will be made sufficiently plain 

 by comparing each of them with the fol- 

 lowing statement of the chief features of 

 that theory. 



. That is, that species originate from one 

 another genetically by a process of trans- 

 formation which requires indefinite time for 

 its accomplishment, and which is, therefore, 

 too slow for actual observation. Such 

 transformation is the result of cumulative 

 repetition, from generation to generation, 

 of small variations such as always prevail 

 in organic forms, until varieties, races, and 

 then species, are produced and the higher 

 groups which they compose are established. 

 Variation is induced and its specific results 

 conserved by physical conditions of en- 

 vironment as a dominant influence and by 



the struggle for existence under which the 

 comparatively few fittest individuals sur- 

 vive and the infinite number of weaklings, 

 which are born of individuals of all species, 

 perish. Species, therefore, have no definite 

 entity, even when fully developed, but are 

 constantly changing toward the production 

 of other species. 



Three of the assumptions which are made 

 by the advocates of this theory are plainly 

 inconsistent with the facts which are pres- 

 ently to be stated, and they only will be 

 discussed on the present occasion. One of 

 them requires the paramount influence of 

 physical conditions of environment for the 

 origination of species and in the conserva- 

 tion of the higher groups >^^hich they con- 

 stitute. One demands immeasurable time 

 for the production of a single species, and 

 consequently the lapse of illimitable time 

 since the beginning of life upon the earth. 

 The other implies that species have no ex- 

 istence as such, but that all of them are in 

 a state of constant change. These assump- 

 tions will be separately considered further 

 on. 



The accompanying diagram is presented 

 for the purpose of illustrating some of the 

 principal facts that are mentioned in the 

 statements which are to follow. 



The horizontal spaces of the diagram 

 represent the respective ages of geological 

 history as they have been determined by 

 the presence and characters of the fossil 

 remains found in their strata. The per- 

 pendicular lines represent the principal 

 great groups of animals and plants whose 

 remains are found there. Thus the five 

 lines under A represent the five subking- 

 doms of marine invertebrates, the Protozoa, 

 Coelenterata, Annuloida, Annulosa and 

 MoUusca. The left-hand line under B 

 represents the non-marine, and the right- 

 hand line the land, invertebrates. C, 

 fishes; left-hand line, selachians; right, 



