AN EXAMINATION OF DARWIN'S ' ' ORIGIN OF 

 SPECIES" IN THE LIGHT OF RECENT 

 OBSERVATIONS AND EXPERIMENTS 



PROFESSOR EDWIN LINTON 

 Washington and Jefferson College 

 About three years ago, some members of a local club, 

 to which the writer belongs, having heard that Darwinism 

 was on its death-bed, a report on the origin of species was 

 ordered. The present paper is made up from notes pre- 

 pared for that occasion. 



In a letter to Hooker, March 9, 1885, Professor Huxley 

 says: 



I have been reading ... the book [Origin of Species] for the nth 

 time. ... It is one of the hardest books to understand thoroughly 

 that I know of, and I suppose that is the reason even people like 

 Romanes get so hopelessly wrong. ("Life and Letters," II, 204.) 



If Huxley, who helped to fight Darwin's battles when 

 1 'The Origin of Species" was young, who talked and 

 argued with its author, can make such a statement con- 

 cerning the book, it is little wonder that people come to 

 different conclusions after reading it now. 



My examination of Darwin's great work in the light 

 of present-day beliefs has resulted in the finding of 

 numerous passages which support the following theses: 



1. Darwin's main thesis is the doctrine of descent as 

 against the theory of the immutability of species. 



2. A secondary thesis accounts for the origin of species 

 by the theory of descent with modification through varia- 

 tion and natural selection. 



3. Two kinds of variations are recognized: (a) Fluctu- 

 ating variations as now understood, but including also 

 variations of such a degree as would make steps in de- 

 velopment as great as those which separate existing 

 varieties, (b) Sudden changes, or sports. 



It is to be observed that this classification of varieties 

 163 



