82 DARWINISM STATED BY DARWIN HIMSELF. 



progeny of a single pair. Even slow-breeding man has 

 doubled in twenty-five years, and at this rate, in less than 

 a thousand years, there would literally not be standing- 

 room for his progeny. Linnaeus has calculated that if an 

 annual plant produced only two seeds — and there is no 

 plant so unproductive as this — and their seedlings next 

 year produced two, and so on, then in twenty years there 

 would be a million plants. The elephant is reckoned the 

 slowest breeder of all known animals, and I have taken 

 some pains to estimate its probable minimum rate of 

 natural increase ; it will be safest to assume that it begins 

 breeding when thirty years old, and goes on breeding till 

 ninety years old, bringing forth six young in the interval, 

 and surviving till one hundred years old ; if this be so, 

 after a period of from seven hundred and forty to seven 

 hundred and fifty years, there would be nearly nineteen 

 million elephants alive, descended from the first pair. 



DEATH INEVITABLE IN THE FIGHT FOR LIFE. 



In a state of nature almost every full- 

 grown plant annually produces seed, and among 

 animals there are very few which do not annually pair. 

 Hence we may confidently assert that all plants and ani- 

 mals are tending to increase at a geometrical ratio, that 

 all would rapidly stock every station in which they could 

 anyhow exist, and that this geometrical tendency to in- 

 crease must be checked by destruction at some period of 

 life. Our familiarity with the larger domestic animals 

 tends, I think, to mislead us : we see no great destruction 

 falling on them, but we do not keep in mind that thou- 

 sands are annually slaughtered for food, and that in a 

 state of nature an equal number would have somehow to 

 be disposed of. 



