378 NATURAL SCIENCE. Nov., 



research, it would indeed be difficult to imagine one more fairly 

 balanced ; and the Professor has been singularl}' successful in empha- 

 sising the saHent points. 



Evolution, as a natural explanation of the origin of the higher 

 forms of life, succeeded the old mythology in Greece, and first 

 developed from the teachings of Thales and Anaximander (b.c. 6ii- 

 547) into those of Aristotle. This great philosopher had a general 

 conception of the origin of higher species by descent from lower 

 species, and he even stated the theory of the Survival of the Fittest, 

 though rejecting it as an explanation of the evolution of adaptive 

 structures. He also believed that there was no fortuity in 

 Evolution, but that the succession of forms of life was due to 

 the action of an internal perfecting principle originally implanted 

 by the Divine Intelligence. In short, the ancient Greeks, with 

 Aristotle as their most brilliant genius, had already discussed the 

 problem of life from three points of view — had enquired whether 

 Intelligent Design is constantly operating in Nature, whether Nature 

 is under the operation of natural causes originally implanted by this 

 mysterious Design, or whether it is governed by natural causes exclu- 

 sively due to the laws of chance from the very beginning. 



During the long Middle Ages the theory of Evolution made no 

 advance, and even in the end retrogressed. Subsequently the rigid 

 conceptions and definitions of species developed in tlie rapid rise of 

 systematic Zoology and Botany were grafted upon the Mosaic account 

 of the Creaiion, establishing a Special Creation theory for the origin of 

 each species. Later still, when it was discovered from Palaeontology 

 that species of different kinds had succeeded each other in time, the 

 " Special Creation" theory was again remodelled to cover a succession 

 of creations extending down almost to the present day. Thus an 

 ecclesiastical dogma developed into a pseudo-scientific theory full 

 of inconsistencies, but stoutly maintained at the time by leading 

 zoologists and botanists. 



In the seventeenth and eighteenth centuries three classes of 

 writers contributed more or less directly to the foundation of the 

 modern study of Evolution. First, there were the industrious 

 naturalists collecting facts ; secondly, the speculators who still held 

 many of the false Greek notions ; and thirdly, the great Natural 

 Philosophers, of whom Bacon, Descartes, and Leibnitz are 

 examples. Of these it is curious to note that the third class did 

 most towards facilitating modern progress. They clearly perceived 

 that the point to which observations should be directed was not 

 the past but the present mutability of species, and further, tb.at 

 this mutability was simply the variation of individuals on an ex- 

 tended scale. In short, these philosophers recognised the gradations 

 of type, the facts of variation, and the bearing of these facts on the 

 production of new species ; they even noted the analogy between the 

 artificial selection practised by man in producing new forms of plants 

 and domestic animals and the production of new forms in Nature. 

 At the same time, it must be added that the Evolution of Life was 

 only made a very subsidiary element in the System of Philosophy 

 they established. 



Coming to later times. Professor Osborn deals very fully and in 

 general fairness with the respective claims of modern evolutionists. 

 His opinion of Treviranus is less high than that commonly held, and 

 he attempts to assign a very definite position to Erasmus Darwin. 

 The concluding section of the book, however, contains more familiar 

 matter than the preceding chapters, and it is unnecessary here to 



