SECT. II. VEGETATION. 19 



from' the root and the atmofphere, and as perfpiring 

 and refpiring, they are more than commonly thought 

 efTential to vegetation; and fo we find that if the ftems, 

 or branches of a plant, are confiderably deprived of 

 them, it becomes ftunted and difeafed, and if any fruit 

 appear, it proceeds flowly in growth, and is ill fla- 

 voured. The quantity of nutriment which a plant 

 derives from the earth, is in proportion to the number 

 and fize of its leaves ; thus that they may uninterrupt- 

 edly perform their offices, they are diftributed in a very 

 diflincf. and feparate mode. 



The under and upper part of leaves are different, and 

 have feparate offices; the under is rough and porous, 

 -as if adapted to imbibe the rifing moifture ot night 

 dews; and the upper, or clofcr, to exclude the groffer 

 parts of the atmofphere, and to imbibe fome finer 

 food, as to " draw the live ether". Thus leaves will 

 not endure to be reverfed, as is feen by the certain and 

 quick return to their right pofition, when forced from 

 it, and till this is effected, they perform not the proper 

 functions of nature. 



That the gloffy furface of leaves have an intimate 

 connection with the light is evident,, as they rife and 

 fall (in a degree, fome plants more and others lefs) as 

 the fun moves. If they are turned from the Jiglit they 

 twiftthemfelves towards it, as if they had enjoyment, 

 and were confcious of the benefit. — The curious will 

 meet with gratification relative to this f abject, by con- 

 futing Hilt's Traa On the Sleep of Plants; or his 

 gardening for October: — a large tolio. 



One of the offices of leaves, feemsto be, to fabtilize, 

 and give- more fpirit to the abundance of nourifhing 

 fap, and to convey it to the little bud* at their foot Jlalk % 

 to whofe welfare they are efTential. 



If the texture of the leaves be fcrutinized, they are 

 found curioufly ramified ; the ribs and fibres ot each 

 feeming much like a fpreading- plant. The ramifica- 

 tions hold a clofe communication with each other; 



fo 



