April lo, 1890] 



NATURE 



531 



finds that there was a solar eclipse on 13, April 28, and an 

 attractive woodcut is given showing the track of the shadow 

 passing over Rome. As a matter of fact, this eclipse 

 began in the Pacific, touched the continent of America 

 about Vancouver,and passed over Canada to the Atlantic : 

 the whole of its path is confined to " regions Caesar never 

 knew." But the list of false deductions is too long and 

 too uninteresting to pursue any further : exact astronomy 

 can lend no support to the chronological system here 

 developed. William E. Plummer. 



THE EVOLUTION OF SEX. 



The Evolution of Sex. By Prof. Patrick Geddes and J. 

 Arthur Thomson. With 104 Illustrations. (London: 

 Walter Scott, 1889.) 



THIS book, say the authors in the preface, has "the 

 difficult task of inviting the criticism of the biologi- 

 cal student, although primarily addressing itself to the 

 general reader or beginner." In attempting to meet these 

 two interests the authors have aimed high : they have 

 aimed at producing a classic. They have brought to the 

 task— as indeed their names guarantee — a wealth of know- 

 ledge, a lucid and attractive method of treatment, and 

 a rich vein of picturesque language. The illustrations are 

 pertinent, and sometimes very good. The index and table 

 of contents are copious, and the summaries and references 

 to literature at the end of each chapter are most useful. 

 In matters of history they are especially good, and 

 advanced biological students will find the abstracts of the 

 views of Eimer, Weismann, Brooks, Hertwig, Haeckel, 

 Wallace, Spencer, Geddes, and many others exceedingly 

 useful. But as writers for the general public the authors 

 have serious if not prohibitive disadvantages. 



General readers demand, with right, that those who 

 speak to them with the voice of authority shall give 

 them the authoritative views. Controversial matter 

 they are only remotely interested in, and when it 

 cannot be avoided they must have it carefully distin- 

 guished from matter beyond controversy. These authors 

 are controversialists from the first page of their book to 

 the last ; they are partisan controversialists offering their 

 wares and their wisdom as accredited doctrine and 

 •determined result. This is no quarrel with the views of 

 the authors. Prof. Geddes and Mr. Thomson are workers 

 well able to command the attention of biologists for their 

 contributions to any controversy. It is a quarrel with the 

 offering of personal views, generalizations, and theories as 

 final, in a series " designed to bring within the reach of 

 the English-speaking public the best that is known and 

 thought in all departments of modern scientific research." 



As is the fashion with neo-Lamarckians, the authors 

 "delight in obtruding their misconceptions of Darwin. 

 Take, for instance, the following statements : — 



" Arguing from the bad effects of close-breeding amwig 

 higher animals, Darwin and others have called attention 

 to the numerous contrivances among plants which are said 

 to render self-fertili/ation impossible. It must again be 

 said that this survival of a very old way of explaining facts 

 —in terms of their final advantage — is not really a causal 

 explanation at all" (p. 74). 



Or, again, on p. 27 ; — 



"As a special case of natural selection Darwin's minor 

 theory {i.e. sexual selection) is open to the objection of 

 being teleological, i.e. of accounting for structures in terms 

 of a final advantage. It is quite open to the logical critic 

 to urge, as a few have done, that the structures to be ex- 

 plained have to be accounted for before, as well as after, 

 the stage when they were developed enough to be useful. 

 The origin, or in other words, the fundamental physio- 

 logical import, of the structures, must be explained before 

 we have a complete or adequate theory of organic 

 evolution." 



Now there can be no doubt of the question here at issue. 

 Readers of Natur?; may remember that some time ago 

 (Nature, December 12, 1889, p. 129) Prof. Ray Lankester 

 a propos of Cope's supposed contribution to the theory of 

 natural selection,^ asked: " How can Mr. Cope presume 

 to tell us this ? Who has ignored it ? When ? and where .' " 

 It is clear that Prof. Geddes and Mr. Thomson imagine 

 that Darwin has ignored this, and that he has done so in 

 his theory of sexual selection, and in his accounts of 

 contrivances in plants to prevent self-fertilization. In a 

 set of works the definite and reiterated purpose of which 

 is to show (i) that variations do occur, (2) that from these, 

 by selection, varieties, species, organs are elaborated 

 and adapted, it is fortunately easy to find chapter and 

 verse conclusive against the view that Darwin could have 

 imagined that selection teleologically causes the variations 

 that give it scope. Will Prof. Geddes and Mr. Thomson 

 refer to the "Descent of Man" (the writer has the second 

 edition before him) .' On p. 240 it is written : — 



" Not only are the laws of inheritance extremely com- 

 plex, but so are the causes which induce and govern 

 variability. The variations thus induced are preserved 

 and accumulated by sexual selection." 



Will Prof. Geddes and Mr. Thomson refer to the 

 "Fertilization of Orchids" (also second edition) .-' On 

 p. 284 it is written : — 



" Thus throughout nature almost every part of each 

 living being has probably served in a slightly modified 

 condition for diverse purposes, and has acted in the living 

 machinery of many ancient and distinct specific forms,'' 



Or, again, on the same page : — 



" This change " (labellum assuming its normal position) 

 *• it is obvious might be simply effected by the continual 

 selection of varieties which had their ovaries less and less 

 twisted ; but if the plant only afforded varieties with the 

 ovarium more twisted, the same end could be attained by 

 the selection of such variations until the flower was turned 

 completely round on its axis." 



Can there be the faintest suspicion that the man who 

 wrote these sentences did not distinguish between the 

 material for selection and the causes producing that 

 material t One more quotation from the authors to 

 show how they misunderstand Darwin's spirit and 

 writings : — 



" The first of these is the still curiously prevalent opinion 

 that, when you have explained the utility or the advantage 

 of a fact, you have accounted for the fact, an opinion 

 ivhich the theory of natural selection has done more to 

 foster than to rebuff. Darwin was indeed himself char- 

 acteristically silent in regard to the origin of sex as 

 well as of many other ' big lifts ' in the organic series " 

 (p. 126). 



' 'I'he key-note of Cope's imagined contribution was, ''Selection cannot 

 explain the origin of anyiliing." 



