342 



NATURE 



[February 7, 1901 



a distinct line of inquiry. In framing his own answer to 

 the question, the author lays stress on the controlling 

 power of heredity, on Darwin's principle of " continuity 

 of variation," or, as he prefers to call it, "sequence of 

 variation," and also on the fact that the variations of the 

 organic environment of a species — the several other 

 species, that is to say, with which it has to keep^« 

 rapport — being subject to similar limitations with its 

 own, are not likely to set it an impossible task in the way 

 of providing fresh adaptations. Moreover, there are 

 usually periods in the history of a species when it has, 

 as it were, a choice of environments, so that the possi- 

 bilities of adaptation open to it are enlarged. This 

 latter position might well have been illustrated by the 

 striking case of certain mimetic butterflies ; amongst 

 which it is often found that species closely allied to one 

 another, and sometimes even the two sexes of the same 

 species, have been drawn apart, so to speak, into separate 

 protected colour-groups ; while still other species of the 

 same affinities occupy intermediate positions, ready, as it 

 were, to throw in their lot with this or that colour-com- 

 bination, according to their needs. The upshot of the 

 author's contention as to variation and adaptation is, 

 that while the range of possible variation is not indefinite, 

 but necessarily limited, the limitation is in no sense due 

 to the direct action of the environment ; still it is this 

 very limitation that renders adaptation possible, by 

 ensuring a supply of such material as' is capable of being 

 moulded by the selective action of the existing external 

 conditions. Variation that took place merely at random, 

 were it conceivable, would almost inevitably consist of 

 all misses and no hits. 



In the second and concluding part of the book, Mr. 

 Headley deals with the application of evolutionary doc- 

 trine to the problems of human development. His 

 treatme nt of this part of the subject, as of the other, 

 shows freshness, vigour and ability ; but he could here 

 hardly avoid raising points of a highly controversial 

 character, and most of his conclusions are likely to be 

 sharply assailed. Adopting in many respects the point 

 of view of Mr. Benjamin Kidd, he discusses at length the 

 origin and influence of the moral sense, and the various 

 conditions that with advancing civilisation tend to defeat 

 or delay the operation of natural selection. The an- 

 tagonism between altruism and the "cosmic process," 

 which was adumbrated by Huxley in his memorable 

 Romanes lecture, receives a careful and extended treat- 

 ment ; and the author states his own conclusion some- 

 what as follows : — The development of human intelligence 

 has in many ways checked the wholesome operation of 

 natural laws. Being capable of exercise in anti-social 

 directions, it has in times past threatened the well-being 

 if not the very existence of the race. From this fate 

 humanity has so far been preserved by the practice of 

 altruism under the sanctions of religion and morality. 

 Supposing this first peril to have been successfully met, 

 there remains the further danger of physical degenera- 

 tion, which may presently become imminent, and the 

 proper treatment of which is among the most important 

 problems that await us. In spite of his indictment of 

 human reason, Mr. Headley is no pessimist. So far from 

 having lost confidence in the future of the race, he looks 

 boldly to the old sanctions, under higher and more en- 

 NO. 1632, VOL. 63 I 



lightened forms of application, to save the human species 

 from physical, as they already have from social disinte- 

 gration. It is obvious that the working out of this idea, 

 which indeed is not attempted by the author himself in 

 any detail, involves considerations which are unsuitable 

 for discussion in a notice like the present. Suffice it to 

 say that Mr. Headley does not write at random ; and 

 that his views challenge attention, whether sympathetic 

 or otherwise. 



Notwithstanding an occasional abruptness and jerki- 

 ness of style, the author writes well and expresses his views 

 with clearness. More care might with advantage have' 

 been bestowed on the proofs ; misprints are not un- 

 common, the punctuation frequently leaves much to be 

 desired, and there is a curious lack of uniformity in the 

 use of scientific names. Some questionable paleontology 

 will be found on p. 105, and some equally doubtful 

 pathology on pp. 246, 247. An inaccurate use of the term 

 "chrysalis" may be noted on p. 59. But in spite of 

 these and other failings the book reaches a high standard 

 of merit, and should appeal to a wide circle of general 

 readers besides those more especially conversant with 

 the subjects of which it treats. F. A. D. 



THE CENTURY OF SCIENTIFIC PROGRESS. 

 The Story of Nineteenth Century Science. By Henry 

 Smith Williams, M.D. Pp. x -t- 476. Illustrated. 

 (London and New York : Harper and Brothers, 1900.) 

 Price 9^. 



THE story is worth telling, for whatever the ages may 

 hold in store they can hardly deprive the nine- 

 teenth century of the distinction of having witnessed a 

 progress in science without a parallel in the earth's his- 

 tory. Each step in advance has served as a starting- 

 point for many others, and the record of the last quarter 

 century, even of the last decade, far surpasses that of the 

 corresponding period at the outset. The opening 

 chapter of this book, " Science at the Beginning of this 

 Century," enables us to realise how immense the gain 

 has been. 



To write such a history is a task on which, at the 

 beginning of the century, an author might have entered 

 with a light heart. Now such an undertaking seems almost 

 an audacity. Scientific omniscience has long become 

 impossible ; but in an age of such rapid progress some- 

 thing of the kind is required for a work like this. The 

 reviewer is in a still worse plight. How can he — probably 

 almost wholly occupied in trying to carry some one road 

 a little farther into the unknown land — be competent to 

 decide whether the author has done full justice to those 

 similarly engaged in other directions ? So I shall speak 

 critically only of my particular subject, and for the rest 

 briefly touch upon the salient features in the author's 

 narrative. The book, I may remark, evidently had its 

 origin on the other side of the Atlantic, so that the"^ 

 illustrations have a slightly American tinge. The same 

 also may sometimes be said of the English. As example, 

 " down " is a new verb to us ; " per hypothesis " jars on 

 the ear ; to say that a man was " then only a novitiate in 

 science," startles any one accustomed to employ the word 

 novice. Such solecisms, however, are but few. The 

 chapter on palaeontology seems oddly placed between 



