172 "^he Philippine Journal of Science lais 



are those of formula and precept, largely of only local applica- 

 tion. The students of the farm school cannot receive the basic 

 scientific training which would enable them either to coordinate 

 or to generalize their results safely, or to understand clearly 

 the reasons back of their practical operations. As Doctor van 

 Hall clearly shows, many of the cacao "experts" of former 

 years commonly failed in this. On the other hand, the college 

 of agriculture requires a thorough preparation in the sciences 

 basic to agriculture, in order that its students may be able to 

 apply more or less sound reasoning to all agricultural phe- 

 nomena and problems that may present themselves, and al.so 

 enable them to adapt their practice and learning, on the basis 

 of intelligent ratiocination, to a wide range of natural con- 

 ditions. The unexpected is the daily diet of the tropical planter. 

 The two books under consideration well represent the college 

 grade of tropical agricultural .science. They are exceedingly 

 rich in the application of modern science to the growing of two 

 very important tropical crops. They probably represent the 

 highest development yet attained in the agronomy of any trop- 

 ical crop. In a number of otherwise great special works on 

 tropical agriculture this aspect — the art and science of produc- 

 ing the crop — has been seriously neglected, due largely, of course, 

 to the lack of the exact data that can only be obtained by 

 comprehensive and long-continued experimentation. This is 

 characteristic of works on cane, for example, in which the 

 manufacturing side has received the major attention ; although, 

 with the highly important results of the past few years, a good 

 preliminary text on the agronomy of cane is now for the first 

 time possible. In a recent very extensive work on cacao only 

 20 pages are devoted to the entire agronomy-side of the subject. 

 While the two present works represent the latest and most com- 

 plete results in the agronomy of these crops, still, all through 

 their pages there are encountered references to points and 

 problems yet unsolved. Doctor van Hall's work is particularly 

 valuable in that it includes a critical review, characterized by 

 clear thinking and technical treatment, of all important previous 

 works on cacao. Such an attempt to coordinate and explain 

 the great diversity of former opinion is of the highest possible 

 importance in the development of tropical agriculture. Formerly 

 the planter or student was quite lost in the maze of diverse local 

 opinion, unless, perchance, there happened to exist works relat- 

 ing to operations in his own locality. Doctor van Hall makes 

 available to the student and to the planter the well-digested 

 results from all regions, although he says nothing calculated 



