HERBERT SPENCER AT SEVENTY-NINE. 551 



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 mat- 

 ter; a chapter on the Dynamic Element in Life, to render less inade- 

 quate the conception of life previously expressed; some pages on 

 Structure; an account, under the head of Cell Life and Cell Multi- 

 plication, of the astonishing actions in cell nuclei which the micro- 

 scope 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 Eecent Criticisms and Hypotheses; a re- 

 writing of most of the chapter on The Argument from Embry- 

 ology; and a number of changes incorporated as sections in pre- 

 existing chapters. The articles on Weissmannism are incorpo- 

 rated 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 chemistry and 

 its derived subjects; Prof. A. G. Tansley in plant morphology and 

 physiology; Prof. E. W. MacBride and Mr. J. T. Cunningham in 

 animal morphology; and Mr. W. B. Hardy in animal physiology. 

 The first volume of this work, recently published, has been received 

 with favor by persons of all shades of opinion respecting the questions 

 it touches. The London Times, in not the friendliest of criticisms, 

 says that even persons who do not accept the author's Philosophy will 

 rejoice that he has been able to complete it, and adds that as it stands 

 it " is a marvel of erudition : every page exhibits the wealth and 

 variety of illustration for which Mr. Spencer is justly famous." The 

 latest notice of it that we have observed, a French one in the Revue 

 Scientifique, says that in consulting it biologists " will not lose their 

 time, and many will find valuable ideas in it, suggestions by which 

 their experimental work can not fail to be greatly benefited. And, 

 like us, they will be filled with admiration for a work so condensed, 

 and at the same time so admirably co-ordinated, so replete with facts 

 and ideas, of the philosopher who has exercised so great an influence 

 on the science of his times, and who is one of the finest intellectual 



