All the acquisitions or losses wrought by nature on individuals, through the influence of the environment in which their race has long been placed, a….

Life, in a body whose order and state of affairs can make it manifest, is assuredly, as I have said, a real power that gives rise to numerous phenome….

All known living bodies are sharply divided into two special kingdoms, based upon the essential differences which distinguish animals from plants, an….

The great age of the earth will appear greater to man when he understands the origin of living organisms and the reasons for the gradual development ….

Habits form a second nature..

One must believe that every living thing whatsoever must change insensibly in its organization and in its form... One must therefore never expect to ….

The form follows the function..

On our planet, all objects are subject to continual and inevitable changes which arise from the essential order of things. These changes take place a….

It is not the organs-that is, the character and form of the animal's bodily parts-that have given rise to its habits and particular structures. It is….

After having produced aquatic animals of all ranks and having caused extensive variations in them by the different environments provided by the water….

What nature does in the course of long periods we do every day when we suddenly change the environment in which some species of living plant is situa….

The thesis that the living creatures have always been composed different species was established in a time where no sufficient observations had been ….

However, if we consider that all the characteristics which have been cited are only differences in degree of structure, may we not suppose that this ….

A sound Physics of the Earth should include all the primary considerations of the earth's atmosphere, of the characteristics and continual changes of….

It is not enough to discover and prove a useful truth previously unknown, but that it is necessary also to be able to propagate it and get it recogni….

Now this circumscribed power, which we have scarcely examined, scarcely studied, this power to whose actions we nearly always attribute an intention ….

In every animal which has not passed the limit of its development, a more frequent and continuous use of any organ gradually strengthens, develops an….

All knowledge that is not the real product of observation, or of consequences deduced from observation, is entirely groundless and illusory..

It is not always the magnitude of the differences observed between species that must determine specific distinctions, but the constant preservation o….