170 FOUNDATIONS OF THE ORIGIN OF SPECIES. [Ch. IX. 



of evolution to the " whole organic kingdom " from plants to 

 man. 



" If we choose to let conjecture run wild, then animals, our 

 fellow brethren in pain, disease, death, suffering and famine — 

 our slaves in the most laborious works, our companions in our 

 amusements — they may partake [of ] our origin in one common 

 ancestor — we may be all melted together." 



" The different intellects of man and animals not so great as 

 between living things without thought (plants), and living 

 things with thought (animals)." 



Speaking of intermediate forms, he remarks : — 



" Opponents will say — show them me. I will answer yes, 

 if you will show me every step between bulldog and grey- 

 hound." 



Here we see that the argument from domestic animals was 

 already present in his mind as bearing on the production of 

 natural species, an argument which he afterwards used with 

 such signal force in the Origin. 



A comparison of the two editions of the Naturalists' Voyage 

 is instructive, as giving some idea of the development of his 

 views on evolution. It does not give us a true index of the 

 mass of conjecture which was taking shape in his mind, but it 

 shows us that he felt sure enough of the truth of his belief to 

 allow a stronger tinge of evolution to appear in the second 

 edition. He has mentioned in the Autobiography (p. 40), that 

 it was not until he read Malthus that he got a clear view of the 

 potency of natural selection. This was in 1838 — a year after 

 he finished the first edition (it was not published until 1839), 

 and seven years before the second edition was issued (1845). 

 Thus the turning-point in the formation of his theory took 

 place between the writing of the two editions. Yet the differ- 

 ence between the two editions is not very marked ; it is 

 another proof of the author's caution and self-restraint in the 

 treatment of his ideas. After reading the second edition of 

 the Voyage we remember with a strong feeling of surprise how 

 far advanced were his views when he wrote it. 



These views are given in the manuscript volume of 1844, 

 mentioned in the Autobiography. I give from my father's 

 Pocket-book the entries referring to the preliminary sketch of 

 this historic essay. 



" 1842, May 18,— Went to Maer. June 15— to Shrewsbury, 

 and 18th to Capel Curig. During my stay at Maer and 

 Shrewsbury. . . . wrote pencil sketch of species theory." * 



* I have discussed in the Life and Letters the statement often made 

 that the first sketch of his theory was written in 1839. 



