on the "Origin of Species" he says: "I believe that animals arc descended from at most only four or five progenitors ; and plants from an equal or lesser number." On the same page,^ however, he goes much further, and says: " Analogy would lead me one step further, namely, to the belief that all animals and plants are descended from some one prototype ; " and he adds that " all the organic beings, which have ever lived on this earth, may be de- scended from some one primordial form." ^ The point of most importance in which Darwin differs from his predecessors is, that he starts with life, they with dead matter. They undertake to account for the origin of life by physical causes ; whereas he assumes the existence of living cells or germs. He does not go into the question of their origin. He assumes them to exist; which would seem of necessity to mvolve the assumption of a Creator. The second important point of difference between the theories in ques- tion is, that those before mentioned account for the diversity of species by the inward power of development, a vis a tergo as it were, i. e., a struggle after improvement ; whereas Darwin refers the origin of species mainly to the laws of nature operating ab extra, killing off the weak or less perfect, and preserving the stronger or more perfect. The third point of difference, so far as the author of the " Vestiges of Creation " is concerned, is that the latter supposes new species to be formed suddenly ; whereas Dar- win holds that they arise by a slow process of very minute changes. They all agree, however, in the main point that all the infinite diversities and marvellous organisms of plants and animals, from the lowest to the highest, are due to the operation of unintelligent physical causes.
The Darwinian theory, therefore, includes the following princi- ples : —
First, that like begets like ; or the law of heredity, according to which throughout the vegetable and animal world, the offspring is like the parent.
Second, the law of variation ; that is, that while in all that is essential the offspring is like the parent, it always differs more or less from its progenitor. These variations are sometimes deterio- rations, sometimes indifferent, sometimes improvements ; that is, such as enable the plant or animal more advantageously to exercise its functions.
1 The Origin of Species by Means of Natural Selection, or the Preservation of Favoured Races in the Struggle for Life, by Charles Darwia, M. A., F. R. S., etc., fifth edition (tenth thousand). London, 1869, p. 572.
a Ibid. p. 573.
14 PART II. Ch. I.— origin OF RL\N.
Third, that as plants and animals increase in a geometrical ratio, they tend to outrun enormously the means of support, and this of necessity gives rise to a continued and universal struggle for life.
Fourth, in this struggle the fittest survive ; that is, those indi- viduals which have an accidental variation of structure which renders them superior to their fellows in the struggle for existence, survive, and transmit that peculiarity to their offspring. This is " natural selection ; " i. e., nature, without intelligence or purpose, selects the individuals best adapted to continue and to improve the race. It is by the operation of these few principles that in the course of countless acres all the diversified forms of vegetables and animals have been produced.
" It is interesting," says Darwin, " to contemplate a tangled bank, clothed with many plants of many kinds, with birds singing on the bushes, with various insects flitting about, and with worms crawling through the damp earth, and to reflect that these elab- orately constructed forms, so different from each other, and depend- ent on each other in so complex a manner, have all been produced by laws acting around us. These laws, taken in the largest sense, being Growth with Reproduction ; Inheritance which is almost implied by reproduction ; Variability from the indirect and direct action of the conditions of life, and from use and disuse ; a Ratio of Increase so hitrh as to lead to a Struo-ffle for Life, and as a con- sequence to Natural Selection, entailing Divergence of Character and the Extinction of less improved forms. Thus, from the war of nature, from famine and death, the most exalted object which we are capable of conceiving, namely, the production of the higher animals, directly follows." ^
Remarks on the Darwinian Theory. First, it shocks the common sense of unsophisticated men to be told that the whale and the humming-bird, man and the mosquito, are derived from the same source. Not that the whale was devel- oped out of the humming-bird, or man out of the musquito, but that both are derived by a slow process of variations continued through countless millions of years. Such is the theory with its scientific feathers plucked off. Nc wonder that at its first promul- gation it was received by the scientific world, not only with surprise, but also with indignation.^ The theory has, indeed, survived this
1 Origin of Species, p. 579.
2 See Proceedings of ike Literary and Philosophical Society of Liverpool during the Fifti- eth Session, 1860-61. This volume contains a paper on Darwin's theory by the president