to follow out the directions of the letter. The work of reading, observing, and experimenting, went on year after year. The puzzling problem of variation among animals and plants yielded to a solution—not a complete one by any means, yet one that was sufficient for the time. The concept of selection grew in importance, until it became the principal feature of the work. Yet as the information accumulated the magnitude of the problem became more clear, and Darwin still hesitated to publish what he considered an incomplete statement of the question and its answer.
During these years of investigation, general interest in the beginning and development of life increased. The same year that Darwin wrote his much-prized sketch, there appeared an anonymous book called the Vestiges of Creation. which some people attributed to Darwin. The book was written in a brilliant style, but particularly in the earlier editions, contained a great number of inaccuracies. As Darwin wrote Hooker, "his geology strikes me as bad, and his zoology far worse," while the general tone of the book was far from philosophic. Yet it did expound an idea of evolution, even though a poor one, and had a very large sale. Even Darwin, devotee to accuracy and caution, admitted that the book did great service in calling attention to the subject, in removing a great deal of prejudice, and in preparing the popular mind for other and more accurate information in the same field.
Finally, in 1856, Lyell persuaded Darwin to prepare his work for publication, and he be-
