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universally active, and the means for the preserva- 

 tion and multiplication of life, are at once simple and 

 grand. 



To enter into more minute details on the vegetable 

 physiology would be incompatible with the objects of 

 these Lectures. I have attempted only to give such 

 general ideas on the subject, as may enable the philo- 

 sophical agriculturist to understand the functions of 

 plants ; those who wish to study the anatomy of ve- 

 getables, as a distinct science, will find abundant ma- 

 terials in the works of the authors I have quoted, 

 page 9, and likewise in the writings of Linnaeus, Des- 

 fontaines, Decandolle, de Saussure, Bonnet, and' 

 Smith. 



The history of the p eculiarities of structure in the 

 different vegetable classes, rather belongs to botanical 

 than agricultural knowledge. As I mentioned in the 

 commencement of this Lecture, their organs are pos- 

 sessed of the most distinct analogies, and are govern- 

 ed by the same laws. In the grasses and palms, the 

 cortical layers are larger in proportion than the other 

 parts ; but their uses seem to be the same as in forest 

 trees. 



In bulbous roots, the alburnous substance forms 

 the largest part of the vegetable ; but in all cases it 

 seems to contain the sap, or solid materials deposited 

 from the sap. 



The slender and comparatively dry leaves of the 

 pine and the cedar perform the same functions as the 

 large and juicy leaves of the fig tree, or the walhut, 



K 



