Reviews and Book-Notices. 251 



the special abunda*ice of sap in spring, whereas it is now a well 

 known fact that such bleeding occurs only when there is great 

 variation in temperature ; that it may occur at any time during 

 the rest period, if the external conditions are favorable ; and that 

 it most generally occurs at a time when the tree contains its 

 minimum of water, ceasing as soon as the leaves develop, and 

 therefore not appearing when there is a maximum of water in the 

 tissues and the greatest physiological movement of water to 

 the leaves and growing parts. These faults, while they are 

 serious for the student who desires to pursue an independent course 

 of study, would largly disappear under the guidance of a com- 

 petent teacher, but they should be eradicated as far as possible. 



While we regret the exceeding brevity which seems to be forced 

 upon the author, this finds some compensation in the remarks of 

 the translator when he says : " It cannot be too strongly impressed 

 upon the student that a mere book knowledge of this, as of any 

 other science, is absolutely valueless. He must make himself 

 practically acquainted with the aid of the microscope, and, if 

 possible, under the guidance of a competent teacher, with the 

 minute structure of plants, and with the life history of the various 

 forms." This is the view which it is important to emphasize and 

 impress upon students and also teachers of graded schools where 

 such subjects find an important place in the course of study. In 

 this light, the treatment of the various subjects may be con- 

 sidered to serve the purpose very well. 



In classification many important changes have been made, 

 bringing this subject fairly well abreast of recent developments. 

 In the general morphology there is a tendency to the introduc- 

 tion of rather more technical terms than is wholly desirable, 

 tending to create confusion in the mind of the young student. 



Taken as a whole, this edition may be regarded as a useful 

 addition to the general text-book series, and will doubless be 

 found to meet a very general demand. 



D. P. P. 



The Report of the Kansas State Horticultural Society* is a 

 most hopeful indication of what American horticulture is likely 

 to become in the future. The con^nts are of a much more 



* Kansas State Horticultural Society,' Annual Report. G.C. 

 Brackett, 8vo., pp. 306. 1884. 



