IS COyCERNING? SECT. 1*1 



continually from the earth, and by the action of the ' 

 sun and air, circulates, rarifies, and distributes itself. 

 This juicy food, swells the little bags, or cells (of 

 ivhich the substance of plants is composed) and fol- 

 lowing the different modifications thereof, filtrates 

 athwart the parts. For example, That which is. 

 most pure and fine, serves to nourish the flowers and 

 fruits ; that which is not supplies the branches, and 

 leaves, and roots \ the most gross and earthy serves 

 for the bark ; and the most oily is for gum and rosm. 

 Just the same as we find it in animah, where the 

 food they receive into the stomach passes afterwards, 

 into the bl6od r circulates into the vessels, and pursu- 

 ing its different degrees of attenuation, serves to> 

 nourish the different parts of the body. 



The STEMS or trunks of plants are for the support 

 of the head, and to convey juices from the roots 

 upwards for the leaves,, branches, &c. and are com- 

 posed (as the roots) of bladders, and various con- 

 duits for air, sap, &c. perpendicular, spiral,- and 

 horizontal from the pith to the bark. These vessels- 

 may be somewhat seen with the naked eye, as in 

 slices of the young shoots of nut, apple-tree, and 

 vine, but very evidently by a microscope. It is ob- 

 servable, that some plants which are weak and pipy 

 have knots at proper distances to strengthen them, 

 and others have daspers to hold them up ; while 

 others are robust enough in stem to brave the fury 

 of a tempest. 



The LEAVES of plants are very variously, but 

 beautifully constructed in their form and substance * 

 and if we consider them as attracting nourishmepfc 

 from the root and the atmosphere, and as perspiring 

 and respiring, they are (more than commonly tliought) 

 essential to vegetation ; and so w r e find thai if the 

 Stems, or branches of a plant, are considerably de- 

 prived of them, it becomes stunted and diseased, 

 3 



