BOOKS AND CURRENT LITERATURE 2()<) 



the illustrations and the general manner of tnnitment, at the same time 

 tliat the appended body of notes has been very greatly augmented, 

 and the number of references to recent literature increased. The trans- 

 lation has been made with freedom but with fidelity to the original and 

 the resulting volume will take a place as one of the most important 

 texts for instruction and reference in botanical establishments. 



The aim of the physiological anatomist is to discover and describe 

 the interrelations of structure and function in plants, but the extent to 

 which anatomy has outrun physiology in the assemblimg of its facts 

 makes physiological anatomy chiefly an attempt to "explain" the find- 

 ings of anatomy in the terms of physiology. Haberlandt regards the 

 discovery of a correlation as an explanation: "Denn Zusammenhange 

 aufdecken heisst erklaren" (German Ed. p. 1). A correlation may sug- 

 gest the ground for an explanation or it may not. All depends upon 

 the extent to which the correlated facts may be determined in common 

 by a third fact or factor, and upon the extent to which the correlation 

 is exclusive as well as inclusive. The whole structure of physiological 

 anatomy appears to have been erected on a foundation of belief that a 

 correlation constitutes an explanation. The actual performance of 

 physiological anatomy has been to describe a large number of correla- 

 tions between structure and function and to classify them. Many of 

 the interpretations of functional value that have been made are so ob- 

 vious that no one would contradict them, many others have already been 

 backed by experiments! evidence. The number of cases in which sup- 

 positions have been made is large, but the future development of the 

 subject may witness an increasing support of physiological evidence 

 for these suppositions. 



The anatomical facts of Haberlandt's volume are presented in a help- 

 ful manner. The classification of the tissue systems is natural and ex- 

 cellent, and the great bulk of the explanations of function are very sug- 

 gestive, even when they have not been substantiated by experiment. 

 There can be no gainsaying the fact that Haberlandt has done much to 

 enliven anatomy and something to steady physiology. The field that 

 he has outHned will be none the less important if it is eventually incor- 

 porated into the domains of ecology and physiology. 



Haberlandt holds a frankly telcological view-point, and states again 

 and again that this or that structure has been developed "for" this or 

 that function. We read that "many shade plants in particular are 

 satisfied with a somewhat scanty supply of light. Nevertheless, every 

 plant endeavors to arrange its photosynthetic tissues in such a manner 



