MODERN BIOLOGY 465 



this difference — that vast expanses of time are available for natural selec- 

 tion, which justifies the assumption that all the manifold forms of life on 

 the earth, both those which have existed and those which still exist, have 

 been developed through its influence. These facts, then — the dissimilarity 

 between the offspring and the parents (that is, variability) and the struggle 

 for existence, with the resultant natural selection — explain, according to 

 Darwin, the origin of species. 



His Zoological works 

 For two decades Darwin kept this theory to himself in an unceasing search 

 for fresh proofs of its universal application. Finally, in 1859, he published 

 it in a work entitled On the Origin of Species by Means of Natural Selection, one 

 of the most famous works of natural history that have ever been written. 

 Even before that, however, he had won a high reputation as the result of 

 a number of monographs on various subjects. Among these may be mentioned 

 two geological treatises: On Volcanic Islands and On Coral Reefs, the latter 

 being specially famous for its universally accepted theory of the arising of 

 atolls or circular reefs through the sinking of the land area around which 

 the coral reefs had originally grown up. Among his zoological works may 

 be especially mentioned an extensive work on the Cirripedia, in which he 

 gives a detailed and exhaustive description of the system and evolutional 

 history of these animal forms — their peculiar dwarf males discovered by 

 him — besides which he has also dealt with the fossil forms of that animal 

 group. Moreover, as editor of the scientific results of the Beagle expedition 

 he contributed much of great value. It was thus a naturalist with a good 

 reputation who came forward with the work on the origin of species. The 

 violent controversy that it occasioned brought immediate world-wide fame 

 to its author. A somewhat detailed account of the main ideas of the work is 

 therefore called for, all the more so as, in spite of its immense popularity, 

 it would seem to have been less widely read in recent times than one might 

 suppose, and the exposition of the theory of origin to be found in the usual 

 text-books has been strongly influenced by that comparative morphology 

 with which Darwin himself was more or less unfamiliar. 



The theory of origin that Darwin created is decidedly characterized by 

 the personality of its founder. Darwin brought to his work, as we have 

 observed above, a deficient theoretical training, particularly in the sphere 

 of anatomy, an intense geographical and systematical interest, and, as a 

 standpoint beyond which he had already advanced some way, a somewhat 

 ingenuous orthodox-Christian belief in the creation. Being a systematist, he 

 saw in the problem of species the central point of biology, and to him the 

 centre of this problem was, in its turn, the problem of creation. This must 

 be borne in mind if we are to understand Darwin's relation to the earlier 

 morphologically inclined generation of scientists of the Cuvier school. 



