﻿438 ' BOTANICAL GAZETTE [june 



biometry and we are not disappointed. However, the author has, wisely 

 enough, avoided an extensive treatment of statistical methods. In the second 

 part, blastogenic variation and those due to the conditions of life are treated 

 in several chapters. In part III, natural selection and adaptive variations 

 are discussed. 



The work contrasts favorably with much that has been written on varia- 

 tion and evolution in a semi-popular way, in that the author retains a firm hold 

 on ascertained fact. There is little special pleading in the book, and large 

 generalizations are sparingly attempted ; results are impartially presented 

 and their obvious import expressed. On the other hand, the author lacks 

 something of that vigor and enthusiasm that one finds in the champion of a 

 cause; and occasionally there is a lack of that critical and unifying spirit 

 that accompanies complete assimilation of the subject. For example, after 

 reviewing Weldon's paper of 1892, our author approves Weldon's conclusion, 

 based on shrimps, that correlation between two organs is "practically con- 

 stant" for different localities. On the next page he mentions Pearson's 

 general dissent from this view, without coming to any decision, while nothing 

 is said of Dr. Lee's paper (1901) where the correlation-coefficient between 

 length and height of head is given, for the Ainos as 0.50 and for the German 

 as o.io, showing an entire absence of constancy. 



On the other hand, the treatment of certain subjects is very good. The 

 imperfect fertility of dissimilar races when crossed is well worked out; new 

 data concerning identical twins are given; the theory of regression is clearly 

 explained and many facts quoted as to the effect of external conditions. In 

 discussing adaptation, the author accepts self-adaptation as a factor subsidi- 

 ary to natural selection. The degeneration of disused organs he finds 

 difficult to account for. He should remember that all " degeneration" is not 

 due to disuse; and that animals with "degenerate" organs, however arisen, 

 can still be adapted if they get into situations where these organs are of no 



use. — C. B. Davenport. 



Two elementary texts. 



Botanical texts for the secondary schools multiply apace. Professor 

 Stevens, of the University of Kansas, has published an Introduction to 

 botany, which has many good features to commend it.' It is an attempt to 

 combine the instruction of the laboratory handbook and the necessary infor- 

 mation of the text-book. To secure the proper relations of laboratory work 

 and reading he has introduced the laboratory directions before the discussion 

 of the topic to which they relate. These directions are in the main clear and 

 concise, and the work for which they provide well chosen. A particularly 

 commendable feature is that the experiments in plant physiology are not only 



^Stevens, William Chase, Introduction to botany, pp. x + 436, figs, 340* 

 Boston: D. C. Heath & Company, 1902. 



