280 NATURAL HISTORY. 



tions (such as those on cleavage and foliation, on the 

 structure of the 'pampas' of South America, and on 

 volcanic islands) are of the highest importance and of 

 permanent value ; and his theory of the Origin of Coral- 

 reefs obtained a world-wide reputation. Darwin, as 

 previously mentioned, also edited the 'Zoology of the 

 Voyage of the Beagle? Subsequently to his return to 

 England, he engaged in special zoological researches, 

 and published his classical ' Monograph of the Cirripedia,' 

 printed by the Ray Society in 1853 ; with a companion 

 volume on the fossil species of the same group, which 

 appeared under the auspices of the Palaeontographical 

 Society. In 1859 appeared the first edition of the 

 ' Origin of Species by means of Natural Selection,' which 

 rendered his name at once famous over the whole 

 civilised world, and which gave rise to more discussion 

 than perhaps has ever been produced by any other 

 scientific book whatever. This work has been translated 

 into almost all European languages, and the English 

 edition now generally used is the sixth, published in 

 1872. Among the works which proceeded from the pen 

 of Dr Darwin during his later years may be enumerated 

 'The Fertilisation of Orchids' (1862); the 'Variations 

 of Animals and Plants under Domestication' (1867); 

 ' The Descent of Man and Selection in Relation to Sex ' 

 (1871); and 'The Expression of the Emotions in Man 

 and Animals' (1873). 



The great principle which Darwin established in con- 

 nection with the highly complex problem of the Origin 

 of Species, is what is known as 'the Theory of Natural 

 Selection, or the Preservation of Favoured Races in the 



