Page:Carroll Lane Fenton - Darwin and the Theory of Evolution.djvu/36

 Rh The Orchid book was Darwin's first venture into botany and it established his position there as other books had established it in geology and zoology. In 1864 he published a paper on Climbing Plants—an effort which cost him four months of labor. Again illness interfered, and the paper was so badly written, and so obscurely phrased that it received little attention. Eleven years later it was rewritten into a book and became very popular.

In 1868 the first volume of the detailed studies of evolution appeared. Of it Darwin says, "It was a big book, and cost me four years and two months hard labour. It gives all my observations and an immense number of facts collected from various sources, about our domestic productions. In the second volume the causes and laws of variation, inheritance, etc., are discussed as far as our present state of Our knowledge permits. Towards the end of the work I give my well abused hypothesis Of Pangenesis." This, briefly stated, supposes that the countless cells which compose the body of an animal or plant are continually throwing off tiny granules, far too small to be seen even microscopically, that accumulate in the reproductive system. Instead of developing in the next generation they may be transmitted in an inactive or dormant state to several generations, and then suddenly become developed. Various combinations of these granules are supposed to influence their appearance or dormancy in the various generations. As a hypothesis Pangenesis was suggestive but not very satisfactory when put to practice, and