Makch 13, 1908] 



SCIENCE 



421 



if necessary, and the work should be de- 

 layed no longer. The development of our 

 waterways and the conservation of our 

 forests are the two most pressing physical 

 needs of the country. They are inter- 

 dependent, and they should be met vigor- 

 ously, together and at once. The ques- 

 tions of organization, powers and appro- 

 priations are now before the congress. 

 There is urgent need for prompt and deci- 

 sive action. 



Theodore Roosevelt 



SGIENTIFIG BOOKS 

 Darwinism To-day. A discussion of present- 

 day scientific criticism of the Darwinian 

 selection theories, together with a brief ac- 

 count of the principal other proposed 

 auxiliary and alternative theories of Spe- 

 cies-Forming. By Vernon L. Kellogg. 

 New York, Henry Holt and Co. 1907. 

 Pp. 403. 



Undoubtedly the best book of its kind, and 

 cordially to be recommended to the student or 

 layman who struggles with the fluctuations of 

 evolutional belief. This commendation, how- 

 ever, will not seem extreme when it is pointed 

 out that this is practically the only book of 

 its class ! For few indeed are the authors 

 who have attempted the herculean task of 

 sifting out the vast literature which has ac- 

 cumulated around the problems of evolution 

 during the past two decades. The present 

 book then is one which fills a decided need. 

 It is brief, clear and contains summaries of 

 general and technical interest which are 

 elsewhere not to be obtained in the English 

 language. Indeed nowhere else will one find 

 attractive digests even of the classical work 

 of Roux, Naegeli and Weismann. The near- 

 est approach to it is Plate's " Tiber die Bedeiit- 

 ung des Darwin'schen Selectionsprincips," of 

 which a translation has never been published. 

 And to this work Professor Kellogg acknowl- 

 edges frankly his great indebtedness. 



Particularly to be commended in the present 

 book is its style. It breathes of the open air, 

 and leads one, oftener than usual in these 



days, away from the click of the microtome. 

 The main test of the book is interesting, its 

 illustrations — there are no pictures, by the 

 way — are chosen discreetly, and technical 

 summaries and discussions are usually tucked 

 away in the form of appendices. 



The author has brought together the ob- 

 jections to old-fashioned natural selection 

 (which have become a lengthy part of post- 

 Darwinian writings) with a fair degTce of 

 completeness. Such objections, off-hand, are 

 these: that natural selection makes for con- 

 stancy not variability; that it produces 

 changes quantitative not qualitative; that it 

 can operate only on great averages, not on 

 individuals ; that it does not account for con- 

 tinued degeneration; that small variations 

 give no " handle " for selection ; that sexual 

 selection is impotent; that it explains the 

 survival not the arrival of new variations; 

 that the struggle for survival of one set of 

 characters leaves the others to fall effetely to 

 panmixia; that great variations are apt to be 

 eliminated by panmixia; that plural varia- 

 tions are necessary to insure the origin of 

 species; that correlated variations are ex- 

 cessively difficult to explain; that there is 

 weakness in the evidence as to the elimination 

 of the unfit. And these objections are threshed 

 out in adequate detail. 



On the other hand, the author considers, 

 but rather incompletely, the replies of the neo- 

 Darwinians to their critics. He examines, for 

 example, the question of the rise of qualita- 

 tive differences by correlation; the importance 

 of the principle of change of function, and 

 the demonstrable value of small fluctuating 

 variations in certain cases. 



In a book of this kind the critical reader is 

 always interested in determining the point of 

 view of the author himself, and in this regard 

 Professor Kellogg is entitled to hold views by 

 virtue of his own valuable studies on matters 

 evolutional. Professor Kellogg, it appears, 

 feels keenly the criticism directed against the 

 Darwinian factor and pronounces early in his 

 work that " each naturalist for himself must 

 decide how vigorous is selection." Withal, 

 however, he realizes the particular lack of and 

 weakness in substitutional explanations. His 



