806 



SCIENCE. 



[N. S. Vol. XXIV. No. 625. 



no less than one hundred plates and forty-six 

 text-figures accompany the one hundred and 

 ninety-nine pages which compose the text. 



The book is divided into two parts, the filrst 

 of which treats of the theory, briefly discuss- 

 ing inheritance, variation, the struggle for 

 existence, mutation, artificial selection, sexual 

 selection, segregation, and the inheritance of 

 parental modifications. The second part con- 

 siders the phenomena explained by the theory, 

 under the headings of comparative anatomy, 

 embryology, paleontology, geographical distri- 

 bution, and the color of animals, and con- 

 eludes with a chapter on the evolution of man 

 and some general considerations. 



Within the brief limits to which the text is 

 confined a consideration of all the factors 

 which have been proposed or recognized as 

 contributing to organic evolution is impos- 

 sible. The difficulty before the author of such 

 a book is to decide what to omit, and, on the 

 whole. Professor Metcalf may be said to have 

 grappled successfully with his difficulty. But 

 little extra space, however, would have been 

 required for a presentation of the theory of 

 orthogenesis, and a brief account of the obser- 

 vations of Bumpus on sparrows and Weldon 

 on Carcinus would have given a more definite 

 meaning to the term ' selection-value.' Fur- 

 ther, it may be remarked, that in the list of 

 works on evolution given in an appendix no 

 mention is made of Haeckel's ' Evolution of 

 Man,' which surely deserves a place in such a 

 list, even if Plate's admirable treatise be ex- 

 cluded, because as yet un-Englished. 



These omissions are, however, but minor 

 faults, if faults they may be called. More 

 deserving of criticism is the title of the book, 

 which is really an exposition of the theory of 

 natural selection. In the popular mind the 

 theories of evolution and natural selection are 

 so intimately associated that recent criticisms 

 of the latter and suggestions of various addi- 

 tional factors of evolution have led, in many 

 cases, to the belief that the doctrine of evolu- 

 tion is tottering on its base and is well-nigh, 

 if not entirely, discredited. Nor is the con- 

 fusion of the two theories altogether confined 

 to the popular mind, and anything which 

 tends to foster it is to be deprecated. Whether 



natural selection in the Darwinian sense 

 stands or falls, the doctrine of evolution re- 

 mains unshaken. 



And this is not the only confusion that ex- 

 ists with regard to the theory. It has been 

 discussed both as a factor in the origin of 

 species and as a factor in the preservation of 

 species, or rather of adaptations which may 

 or may not be specific. In its former appli- 

 cation it is certainly open to criticism ; in the 

 latter, and stated as the theory of the elim- 

 ination of the unfit, it is almost self-evident. 



Professor Metcalf's book, unfortunately, 

 tends to perpetuate these confusions ; but even 

 with this fault it is a book worth reading and 

 well deserves its success. 



J. P. McM. 



The Microscopy of Vegetable Foods, with 

 special reference to the detection of adul- 

 teration and the diagnosis of mixtures. By 

 Andrew L. Winton, Ph.D., in charge of the 

 Analytical Laboratory of the Connecticut 

 Agricultural Experiment Station, Instructor 

 in Proximate Organic Analysis in the Shef- 

 field Scientific School of Yale University. 

 With the collaboration of Dr. Josef Moel- 

 LER, Professor of Pharmacology, and Head 

 of the Pharmacological Institute of the 

 University of Graz. With 589 illustrations. 

 New York, John Wiley and Sons; London, 

 Chapman and Hall, Limited. 

 This work is a very timely one in view of 

 the fact that the pure-food bill will go into 

 effect on January 1, 1907. Owing to the 

 importance of the subject, whether from the 

 point of view of the manufacturer or that of 

 the consumer, it seems rather strange that 

 until now so few good working books have 

 appeared on this subject. While there are 

 several good books by German authors on the 

 subject of the microscopical examination of 

 foods, there is nothing that can compare with 

 the volume at hand. 



Both Doctors Winton and Moeller are well 

 known for their valuable researches on the 

 subject of food products. Dr. Winton is a 

 former student of the eminent pharmacog- 

 nosist. Professor Moeller, and it is rather 

 unique to find a student associated with his 



