OOUESE SECOND. 



VEGETABLE ANATOMY AND PHYSIOLOGY. 



THAT branch of the science of botany with which 

 you have been thus far occupied is called Organogra- 

 phy, which describes the external parts of plants in 

 respect to their forms. You are now to take up the 

 study of vegetable anatomy, or the minute structure 

 of plants as revealed by the microscope. These two 

 departments of the science constitute structural bot- 

 any, in which the plant is regarded without reference 

 to its activities. The study of the plant in action, 

 or vegetable physiology, will conclude the volume. 



To study the internal parts of plants by direct 

 observation you must have a microscope that will 

 magnify from forty to eighty diameters. You may 

 read descriptions, and see pictures of cells, fibres, and 

 vessels, and their relations in the living structure, and 

 so get an idea of the subject, which is better than none 

 at all ; but knowledge so gained is very imperfect, from 

 its vagueness and want of reality. Besides, when 

 statements are taken at second-hand, the learner loses 

 the educational effect of search and discovery, and 

 has not the interest or enthusiasm which is awakened 

 by impressions of the things themselves. 



