February 2], 1913] 



SCIENCE 



305 



also rather crude, but later becoming more 

 and more refined, until finally it lias become 

 almost if not quite metaphysical. To Pro- 

 fessor Greil, however, preformationism in any 

 of its forms is a stone of stumbling and a 

 rock of offense, and in the two volumes now 

 before us he attempts to recall the feet of the 

 faitliful to the paths of epigenesis, by what he 

 terms, with insistence, a formal or descriptive 

 analysis of the phenomena of development. 



He starts, however, with a basic proposition, 

 " the true and fundamental principle of ra- 

 tional comparative embryology," which he ex- 

 presses in the words of Haeckel, " Aus Gleich- 

 artigem Ungleiehartiges." He is thus an 

 epigenesist of the epigenesists and his method 

 of analysis is to proceed from this assumed 

 truth to reconstruction of the embryological 

 history. The first part of the treatise is prac- 

 tically a reprint of a paper recently published 

 in the Zoologische Jahrbilcher^ and is a de- 

 scription of the phenomena of development as 

 seen by a thorough-going epigenesist, who is 

 also a firm believer in the biogenetic law. 

 In the second part special problems, such as 

 adaptation and variability, inheritance and 

 sex-determination, are similarly surveyed and 

 in a somewhat extended appendix the various 

 theories of Eoux, E. Hertwig, Eabl, Mehnert, 

 Kassawitz, Fick and Godlewski are reviewed 

 and criticized, with the same richness of dia- 

 lectic that pervades the entire work. 



For the author wields the pen of a ready 

 writer, which unfortunately frequently leads 

 him into unnecessary repetitions and verbosi- 

 ties, which extend over seven hundred pages 

 what might have been clearly and forcibly 

 presented in perhaps half the space, to the 

 greater comfort and satisfaction of the reader. 

 But even with due allowance for redundancies, 

 the ground covered is so extensive as to pre- 

 clude the possibility of a review or even a bare 

 enumeration of the various questions dis- 

 cussed, and it must suffice to repeat that the 

 main thesis of the work is the all-sufficiency 



'A. Greil, "Ueber allgemeine Eichtlinien des 

 Entwieklungs- und Vererbungsprobleme, ' ' Zool. 

 JahrT}., Bd. XXXI., Abt. fiir allgem. Zool. und 

 Physiol, der Tiere, 1912. 



of epigenesis. That is the one and only power, 

 and formal analysis is its prophet. Professor 

 Greil presents a strong case, but it must be 

 confessed that he does not and, indeed, in the 

 present state of our knowledge, he can not yet 

 remove the difficulty that has forced so many 

 thinking zoologists into preformationism, 

 namely, an explanation of how differentiation 

 is possible by epigenesis. One may glibly 

 talk of cellular interaction, of effects produced 

 by quantity and quality of the food and by the 

 outside environment, and of the determina- 

 tion resulting for the chemical constitution 

 of the ovum, but until we have concrete evi- 

 dence of how these or other factors act in the 

 production of differentiation epigenesis will 

 continue to be no explanation. And, after 

 all, if the last named of the above factors be 

 admitted, is it not merely carrying preforma- 

 tionism back to its ultimate limits and making 

 it identical with epigenesis? 



J. P. McM. 



Origin and Antiquity of Man. By G. 



Fhedeeick Wright, D.D., LL.D., F.G.S.A. 



Oberlin, Ohio, Bibliotheca Sacra Company. 



1912. Pp. XX -1-547. Illustrated. 



As an introduction Professor Wright dis- 

 cusses the origin and antiquity of the earth. 

 He inclines toward a very moderate estimate 

 of the length of geologic time and hence of 

 the human period, which began when man 

 became a tool-user. To him the ancient 

 civilizations of Babylonia, Egypt, Crete and 

 Central Asia were of a high order. These 

 rare blossoms in the springtime of history 

 were each nurtured by exceptional geniuses 

 instead of being the product of a gradual 

 unfolding. 



The diversity of languages is invoked as an 

 aid in the measurement of man's antiquity. 

 In view of the rapidity with which children 

 when isolated invent a language of their own, 

 the author believes the evidence of an ex- 

 tremely great antiquity of the human race 

 drawn from the diversity of language at the 

 dawn of history to be far from conclusive. 



In the chapter on the " Origin of the Eaces 

 of Europe" (p. 105), the author states that 



