I am quite conscious that my speculations run beyond the bounds of true science....It is a mere rag of an hypothesis with as many flaw[s] & holes as sound parts.

We cannot fathom the marvelous complexity of an organic being; but on the hypothesis here advanced this complexity is much increased. Each living creature must be looked at as a microcosm--a little universe, formed of a host of self-propagating organisms, inconceivably minute and as numerous as the stars in heaven.

It may be doubted that there are many other animals which have played so important a part in the history of the world as have these lowly organized creatures.

If a person asked my advice, before undertaking a long voyage, my answer would depend upon his possessing a decided taste for some branch of knowledge, which could by this means be advanced. No doubt it is a high satisfaction to behold various countries and the many races of mankind, but the pleasures gained at the time do not counterbalance the evils.

The age-old and noble thought of 'I will lay down my life to save another,' is nothing more than cowardice.

But Geology carries the day: it is like the pleasure of gambling, speculating, on first arriving, what the rocks may be; I often mentally cry out 3 to 1 Tertiary against primitive; but the latter have hitherto won all the bets.

Great is the power of steady misrepresentation; but the history of science shows that fortunately this power does not long endure.