Page:Darwin - The various contrivances by which orchids are fertilized by insects (1877).djvu/21

 ON THE

&c. &c.

INTRODUCTION.

object of the following work is to show that the contrivances by which Orchids are fertilised, are as varied and almost as perfect as any of the most beautiful adaptations in the animal kingdom; and, secondly, to show that these contrivances have for their main object the fertilisation of the flowers with pollen brought by insects from a distinct plant. In my volume 'On the Origin of Species' I gave only general reasons for the belief that it is an almost universal law of nature that the higher organic beings require an occasional cross with another individual; or, which is the same thing, that no hermaphrodite fertilises itself for a perpetuity of generations. Having been blamed for propounding this doctrine without giving ample facts, for which I had not sufficient space in that work, I wish here to show that I have not spoken without having gone into details.

I have been led to publish this little treatise separately, as it is too large to be incorporated with any other subject. As Orchids are universally acknowledged to rank amongst the most singular and most