246 



SCIENCE 



[N. S. Vol. XL. No. 1024 



portant advances which have been made in 

 the study of evolution since the time of Dar- 

 vein, namely the theories of Weismann and 

 Mendel. 



For whether one accepts or rejects these 

 theories, no one will question their great value 

 in stimulating research concerning evolution- 

 ary problems, the productiveness of which has 

 been enormous in the last thirty years. 



It was in the early eighties that Weismann 

 in his essays on heredity challenged the gen- 

 eral belief in the inheritance of acquired char- 

 acters and pointed out the logical distinction 

 between soma and germ-plasm, which despite 

 numberless attacks still stands. Ten years 

 later " The Germ-plasm " theory was pub- 

 lished in its fully developed form, and after 

 another decade of debate and study " The 

 Evolution Theory " was published, in which 

 Weismann attempted to make a comprehen- 

 sive survey of the entire field of evolution as 

 seen in the light of his germ-plasm theory. 

 In the first sentence of his preface, as trans- 

 lated by Thomson, he says : " When a life of 

 pleasant labor is drawing to a close, the wish 

 naturally asserts itself to gather together the 

 main results, and to combine them in a well- 

 defined and harmonious picture which may 

 be left as a legacy to succeeding generations." 

 Succeeding generations have reason to be 

 grateful to Weismann that he undertook thus 

 to present his mature views. Few books on 

 evolution since the publication of Darwin's 

 " Origin of Species " can be read with greater 

 pleasure or profit than this, or are likely longer 

 to survive. To English readers it is accessible 

 in a faithful translation made by Professor 

 and Mrs. J. A. Thomson in their usual clear 

 and graceful style. 



The popularity of the original is shown by 

 the fact that a second edition was called for 

 within two years, the third and doubtless final 

 edition being the one before us. In the second 

 edition few changes were made, beyond the 

 addition of a few notes, but by the time the 

 third edition was issued (1913) Mendelism 

 had so far developed as to call for extended 

 review. Weismann welcomes Mendelism as a 

 confirmation of the basic idea of his germ- 



plasm theory, the doctrine of determiners. 

 Mutation he rejects as inconsistent with the 

 view that adaptations arise gradually through 

 the action of natural selection. 



Bateson's book, first published in 1909, may 

 be regarded as the authoritative interpreta- 

 tion of Mendelism. It contains a biography 

 and three portraits of Mendel with a transla- 

 tion of his original papers, and also a compre- 

 hensive account of Mendelian principles as 

 developed by the Bateson-Punnett group of 

 workers at Cambridge University. The first 

 edition of the book was exhausted within a few 

 months of its publication and it was then re- 

 printed without change. The present " third 

 impression " was taken advantage of to add 

 " a series of brief appendices to acquaint the 

 reader with the nature of the principal ad- 

 vances made, while awaiting an opportunity 

 of rewriting the book." The " appendices " 

 mentioned consist of brief notices of subse- 

 quent publications, which, however, fail to give 

 an adequate notion of their content, or of the 

 direction which the further development of 

 Mendelism has taken since 1909. The book is 

 rightly and honestly called a "third impres- 

 sion," not a new edition. It is essentially a 

 portrait of the Mendelism of 1909, and seeks 

 to combine the fundamental idea in the germ- 

 plasm theory (that of determiners) with the 

 fundamental idea in mutation (that of the 

 sudden origin of characters). 



W. E. Castle 



SPECIAL ABTICLES 



A NEW METHOD FOR THE DETERMINATION OP 

 SOIL ACIDITY ^ 



Soil acidity problems are at the present 

 time, perhaps, the most important of all soil 

 problems confronting the farmers of Wiscon- 

 sin and many other states. In studying these 

 problems one of the most serious drawbacks 

 has been the lack of suitable qualitative and 

 quantitative methods for the determination of 

 this acidity. The litmus-paper test when 

 properly made is a fairly satisfactory qualita- 

 tive test and has been our most reliable test. 



1 Publication authorized by the Director of the 

 Wis. Expt. Station. 



