The most important factor in survival is neither intelligence nor strength but adaptability.

As buds give rise by growth to fresh buds, and these, if vigorous, branch out and overtop on all sides many a feebler branch, so by generation I believe it has been with the great Tree of Life, which fills with its dead and broken branches the crust of the earth, and covers the surface with its ever branching and beautiful ramifications.

The theory which I would offer, is simply, that as the land with the attached reefs subsides very gradually from the action of subterranean causes, the coral-building polypi soon raise again their solid masses to the level of the water: but not so with the land; each inch lost is irreclaimably gone; as the whole gradually sinks, the water gains foot by foot on the shore, till the last and highest peak is finally submerged.

The tree of life should perhaps be called the coral of life, base of branches dead; so that passages cannot be seen-this again offers contradiction to constant succession of germs in progress.

We may confidently come to the conclusion, that the forces which slowly and by little starts uplift continents, and that those which at successive periods pour forth volcanic matter from open orifices, are identical.

The most energetic workers I have encountered in my world travels are the vegetarian miners of Chile.

For I am well aware that scarcely a single point is discussed in this volume on which facts cannot be adduced, often apparently leading to conclusions directly opposite to those at which I have arrived. A fair result can be obtained only by fully stating and balancing the facts and arguments on both sides of each question.