PHYSIOLOGY, STRUCTURE, FUNCTIONS, AND 

 NATURAL ARRANGEMENT 



PLANTS, 



(extracted and condensed, chiefly from Richard's nouveaux 



E'LE'MENS, 8vO. translated by CLINTON.) 



It is difficult to draw precisely the line of demarcation 

 between the vegetable and animal. We may, however, find 

 well-marked differences between animals and vegetables. In 

 the animal, is a system of contractile fibres, whose state of 

 relaxation or of tension determines the motion of the animal ; 

 these are the muscular fibres, wanting in the vegetable. In 

 vegetables, there is properly speaking no circulation ; the 

 nutritious fluids are difi^used through the vegetable, but they 

 want that agent of impulse, the heart, which, in animals, is 

 the point from which the blood takes its departure, and to 

 which it finally returns. 



It may be observed, that vegetables are composed of simple 

 and similar elementary parts, which, combined in various ways, 

 constitute organs. 



The Elementary Parts of Vegetables, 



The internal organization of a vegetable is composed of 

 cells with thin, transparent partitions, (or walls,) extremely 

 minute, and of various forms, sometimes regular, sometimes 

 irregular, and of cylindrical tubes, either scattered, or united 

 in bundles. These two forms of the elementary parts of vege- 

 tables, have received the names of 1. cellular tissue, and oi 2. 

 vascular tissue. See Plate, H. fig. 163, cellular tissue. 



d 2 



