28 VEGETABLE ORGANOGRAPHY. 



CHAPTER III. 



OF THE VESSELS. 



Section I. — Of the Vessels in general. 



Of all the parts of vegetable anatomy, the structure 

 and history of the Vessels is that about which there has 

 been most dispute, and upon which there is still but 

 little accordance. 



We describe under this name (adopted from analogy 

 with animal anatomy) those cylindrical, or nearly cylin-^ 

 drical tubes, which are observed in the greater number 

 of vegetables ; and which differ from even the most elon- 

 gated cellules, both because there is not found in them 

 any diaphragm which closes them in a transverse direc- 

 tion, and because their walls are marked with dots, 

 stripes, rings, slits, or spires, which are not to be found 

 on the walls of cellules. 



For a long time, vessels have been distinguished into 

 Proper Vessels, and Lymphatic Vessels. Under the for- 

 mer name were described the tubular cavities which con- 

 tained the peculiar juices of certain plants ; such as the 

 milky, resinous, &c. Under the second were compre- 

 hended all the tubes full of air, or of water, which is 

 but little if at all elaborated. But it has been since 



