Marks of honor offered to Mr. Spencer from time to time since 1871 have included doctor's degrees from the Universities of St. Andrews, Bologna, Cambridge, Edinburgh, and Buda-Pesth; and elections as foreign member or correspondent of the Academies of Rome, Turin, Naples, Paris, Philadelphia, Copenhagen, Brussels, Vienna, Milan, and the Prussian order "_Pour le Mérite_." Mr. Spencer has been prompted year after year to decline these various honors by the conviction that instead of being, as commonly supposed, encouragements to literature and science, they are discouraging. He contends that they constitute a system of inverse handicapping. In physical competitions it is usual to give the younger a certain artificial advantage when they are set against the elder; but in these mental competitions between the rising men and the men who have risen the reverse practice is followed--the men who have risen have an artificial advantage, and the younger men, who of necessity have much to struggle against, have their difficulties artificially increased by the absence of titles which their competitors possess. Mr. Spencer is quite aware that the course he has persistently followed has cost him much, since a list of honors on the title-pages of his books would have greatly increased the attention paid to them by critics and others. Nevertheless, he has continued to make this practical protest. Since completing his Philosophy, Mr. Spencer has occupied his working hours with the revision of the Principles of Biology, making the modifications and incorporating the new facts which the progress of the science demands. He recognizes that the advance has been more rapid in this branch than in any other; and that while it might be almost hopeless for him at his time of life to bring a work on biology at large up to date, the case is different in an exposition of the Principles of Biology. The additions to the work include a chapter on Metabolism supplementing the discussion of vital changes of matter; a chapter on the Dynamic Element in Life, to render less inadequate the conception of life previously expressed; some pages on Structure; an account, under the head of Cell Life and Cell Multiplication, of the astonishing actions in cell nuclei which the microscope has revealed; a further chapter on Genesis, Heredity, and Variation, in which certain views enunciated in the first edition of the book are qualified and developed; a review of various modern ideas under the title of Recent Criticisms and Hypotheses; a rewriting of most of the chapter on The Argument from Embryology; and a number of changes incorporated as sections in pre-existing chapters. The articles on Weissmannism are incorporated in an appendix. In performing this work assistance was needed, and the author sought and received criticism and help from different persons, each taking a division falling within the range of his special studies: Prof. W. H. Perkin in organic