208 THE METHOD OF DARWIN. 



sions of the materials which he had collected, 

 some of the most striking are his chapters on 

 pigeons, 1 in which he considered the variation 

 of breeds, individual differences, and skeletal 

 differences; the discussion in the second volume 

 of the "Variation of Animals and Plants under 

 Domestication " ; the exhaustive analysis of his 

 materials in reaching his general conclusions 

 on the effects of cross- and self-fertilization; 

 and his repeated discussions of the cement 

 glands of Cirripedia, and of the parasitic and 

 complemental males on the hermaphrodite 

 "females," and the reasons for regarding them 

 as such rather than as independent forms. 2 

 But the general discussion that is typical both 

 from the general interest of the subject and 

 the compactness and symmetry of the argument 

 is the work on the " Origin of Species."" It 

 would be impossible to analyze such a far- 

 reaching argument without restating it. Doubt- 

 less criticisms could be made against the 

 arrangement of materials and the order of dis- 

 cussion, and against the nature of the evidence 

 adduced. It is not intended here to raise the 



1 Variation of Animals and Plants under Domestication, 

 Vol. I. pp. I37-235- 



2 Monograph of Cirripedia, Vol. I. pp. 38, 180-293, Vol. II. 

 pp. 23-30, 151. 



