BOOK REVIEWS. 



663 



Aster with its innumerable species with endless intergrades, and says, 

 " Natural selection would seem to be an adequate explanation of the 

 situation." Bentham long ago said there were no good characters for 

 separating the ninety genera of the sub-tribes of Asteroideae. We 

 should have thought this was an excellent case to prove the non- 

 existence of natural selection, for every conceivable variety exists! 

 Like Hieracium, it is evidently a genus of easy adaptation. 



He says the botanist " cannot discover how it [Natural Selection] 

 can really originate new characters. " Of course it cannot. Darwin told 

 us it only stands for a metaphor, and per se can do nothing. He is 

 quite right in observing " the greatest difficulty with natural selection 

 is adaptation." Ecology has quite upset the old ideas— e.^. that 

 prickles were to ward off browsing animals. Such an a priori, assumed 

 adaptation, is simply teleological ; whereas we now know that plants 

 automatically " respond " to the environment. One result being 

 spines, under drought, and dissected submerged leaves under water. 



Mr. MacDougal deals with this subject under the title '* The Direct 

 Influence of the Environment " ; but he does not appear to be very 

 familiar with the subject, for he says an arid atmosphere or intense 

 insolation would affect leaves chiefly ; while unusual soil concentrations 

 would influence roots, only'. Desert plants would show the inade- 

 quacy of the first statement, and halophytes the second. He then 

 considers experiments on the germ-cells in hens, and refers to many 

 animals and plants which under experiments failed to show that the 

 offspring were affected. The' reason is obvious. In nature the here- 

 ditary traits originating as' acquired characters were due to natural 

 responses to external natural conditions; and then, many generations 

 are mostly required to fix them. Mutilations, e.g., are not " the direct 

 action of the- environment " nor the source of varietal characters. 



Mr. Eigenmann also deals with " Adaptation " from the zoological 

 point of view, but inverts the process. Thus, he says, " Fish selected 

 the places adapted to each species. Blind cave fishes do not have 

 degenerate eyes because they live in caves ; but they live in caves 

 because their ancestors were adjusted to do without the use of the 

 eye." One naturally asks how did they find out where the caves 

 were? The author is evidently not aware of de Vire's experiments on 

 blind anim^als of caves [Comptes Rendus). 



The other addresses mainly deal with zoology, so need not be here 

 discussed. Th-e volume is very interesting, but the authors appear to 

 be unaware of the vast importance of ecology in interpreting nature. 



"Hereditary Characters and ;their Modes of Transmission." By 

 C. E. Walker, M.E.C.S., &c. 8vo., 239 pp. . (Arnold, London, 1910.) 

 8s. 6d. net. 



This book contains twelve chapters. Bibliography, and Index. They 

 deal with—" The Structure of Living Matter " ; " The Cell in Animals 

 and Plants : its Structure, Division and Differentiation"; "Varia- 

 tion, Mutation "; " Adaption "; " Inborn Characters "; " Causes 



