If I had not been so great an invalid, I should not have done so much as I have accomplished.

Often a cold shudder has run through me, and I have asked myself whether I may have not devoted myself to a fantasy.

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

It is a truly wonderful fact - the wonder of which we are apt to overlook from familiarity - that all animals and all plants throughout all time and space should be related to each other in group subordinate to group.

Progress has been much more general than retrogression

I would give absolutely nothing for the theory of Natural Selection, if it requires miraculous additions at any one stage of descent.

When the sexes differ in beauty, in the power of singing, or in producing what I have called instrumental music, it is almost invariably the male which excels the female.