12 THE FOUNDATIONS OF THE 'ORIGIN OF SPECIES.' 



remain as it now stands, conveying, as it clearly does, the 

 impression that 1839 was the date of his earliest written sketch. 

 The sketch of 1844 is written in a clerk's hand, in two 

 hundred and .thirty-one pages folio, blank leaves being 

 alternated with the MS. with a view to amplification. The 

 text has been revised and corrected, criticisms being pencilled 

 by himself on the margin. It is divided into two parts : I. " On 

 the variation of Organic Beings under Domestication and in 

 their Natural State." II. "On the Evidence favourable and 

 opposed to the view that Species are naturally formed races 

 descended from common Stocks." The first part contains the 

 main argument of the ' Origin of Species.' It is founded, as is 

 the argument of that work, on the study of domestic animals, 

 and both the Sketch and the ' Origin ' open with a chapter 

 on variation under domestication and on artificial selection. 

 This is followed, in both essays, by discussions on variation 

 under nature, on natural selection, and on the struggle for 

 life. Here, any close resemblance between the two essays 

 with regard to arrangement ceases. Chapter III. of the 

 Sketch, which concludes the first part, treats of the varia- 

 tions which occur in the instincts and habits of animals, 

 and thus corresponds to some extent with Chapter VII. of 

 the 'Origin' (1st edit.). It thus forms a complement to 

 the chapters which deal with variation in structure. It seems 

 to have been placed thus early in the Essay to prevent the 

 hasty rejection of the whole theory by a reader to whom 

 the idea of natural selection acting on instincts might seem 

 impossible. This is the more probable, as the Chapter on 

 Instinct in the ' Origin ' is specially mentioned (Introduction, 

 p. 5) as one of the " most apparent and gravest difficulties on 

 the theory." Moreover the chapter in the Sketch ends with 

 a discussion, "whether any particular corporeal structures 



are so wonderful as to justify the rejection prima facie 



of our theory." Under this heading comes the discussion of 

 the eye, which in the ' Origin ' finds its place in Chapter VI. 



