THE ORIGIN OF SPECIES. lOB 



January, 1860, the third (seventh thousand) in 1861, 

 the fourth (eighth thousand) in 1866, the fifth (tenth 

 thousand) in 1869, the sixth in 1872 : in 1887 the 

 twenty-fourth thousand was reached. 



A note to the last edition states that the second 

 " was little more than a reprint of the first. The 

 third edition was largely corrected and added to, and 

 the fourth and fifth still more largely." The sixth 

 edition also contains "numerous small corrections," 

 and is about one-fourth larger than the first edition, 

 although this material is, owing to the smaller print 

 and more crow^ded lines, compressed into a smaller 

 number of pages. The sixth edition also differs from 

 the first in containing a glossary, an historical sketch, 

 and a note and list of the chief corrections. 



The titles of Chapters I., II., and III. remain the 

 same in the first and last editions. Herbert Spencer's 

 phrase is added to Darwin's term, as the heading of 

 Chapter IV., which accordingly becomes in the last 

 edition " Natural Selection ; or the Survival of the 

 Fittest." This change was certainly introduced in 

 order to help readers to grasp the meaning of Darwin's 

 title, which had been very generally misunderstood. 

 The heading of Chapter V. remains the same, while 

 in Chapter YI.—" Difficulties on Theory"— "on" is 

 replaced by "of the." This chapter is, in the last 

 edition, succeeded by a new one dealing with many 

 of the difficulties which had been raised or had 

 occurred to Darwin in the interval between the two 

 editions ; it is headed " Miscellaneous Objections to 



