Every species has come into existence coincident both in space and time with a pre-existing closely allied species.

Every species has come into existence coincident both in space and time with a pre-existing closely allied species.

Truth is born into this world only with pangs and tribulations, and every fresh truth is received unwillingly. To expect the world to receive a new truth, or even an old truth, without challenging it, is to look for one of those miracles which do not occur.

It has been generally the custom of writers on natural history to take the habits and instincts of animals as the fixed point, and to consider their structure and organization as specially adapted to be in accordance with them.

Modification of form is admitted to be a matter of time

As well might it be said that, because we are ignorant of the laws by which metals are produced and trees developed, we cannot know anything of the origin of steamships and railways

There is a tendency in nature to the continued progression of certain classes of varieties further and further from the original type.