In enlarging the Essay of 1842 into that of 1844, the author retained the sections of the sketch as chapters in the completer presentment. It follows that what has been said of the relation of the earlier Essay to the _Origin_ is generally true of the 1844 Essay. In the latter, however, the geological discussion is, clearly instead of obscurely, divided into two chapters, which correspond roughly with Chapters IX and X of the _Origin_. But part of the contents of Chapter X (_Origin_) occurs in Chapter VI (1844) on Geographical Distribution. The treatment of distribution is particularly full and interesting in the 1844 Essay, but the arrangement of the material, especially the introduction of Sec. III. p. 183, leads to some repetition which is avoided in the _Origin_. It should be noted that Hybridism, which has a separate chapter (VIII) in the _Origin_, is treated in Chapter II of the Essay. Finally that Chapter XIII (_Origin_) corresponds to Chapters VII, VIII and IX of the work of 1844. The fact that in 1842, seventeen years before the publication of the _Origin_, my father should have been able to write out so full an outline of his future work, is very remarkable. In his Autobiography{25} he writes of the 1844 Essay, "But at that time I overlooked one problem of great importance.... This problem is the tendency in organic beings descended from the same stock to diverge in character as they become modified." The absence of the principle of divergence is of course also a characteristic of the sketch of 1842. But at p. 37, the author is not far from this point of view. The passage referred to is: "If any species, _A_, in changing gets an advantage and that advantage ... is inherited, _A_ will be the progenitor of several genera or even families in the hard struggle of nature. _A_ will go on beating out other forms, it might come that _A_ would people <the> earth,--we may now not have one descendant on our globe of the one or several original creations{26}." But if the descendants of _A_ have peopled the earth by beating out other forms, they must have diverged in occupying the innumerable diverse modes of life from which they expelled their predecessors. What I wrote{27} on this subject in 1887 is I think true: "Descent with modification implies divergence, and we become so habituated to a belief in descent, and therefore in divergence, that we do not notice the absence of proof that divergence is in itself an advantage." {25} _Life and Letters_, i. p. 84. {26} In the footnotes to the Essay of 1844 attention is called to similar passages. {27} _Life and Letters_, ii. p. 15.