SKCT. 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 ft ems, 

 or branches of a plant, are confiderably deprived of 

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

 appear, it proceeds flowiy 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 ctiftributed in a very 

 diftincl: 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 of night 

 dews; and the upper, or ciofer 3 to exclude the groffer 

 j>arts of the atmofphere, and to imbibe fome finer 

 food, as to 44 draw the live ether". Thus leaves will 

 riot endure to be reverfed, as is feen by the certain and 

 cjuick return to their right pofition, when forced from 

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

 funftions of nature. 



That the gloffy Jurface of leaves have an intimate 

 connexion 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 light they 

 twift themfelves towards it, as if they had enjoyment, 

 and were conjclcus of the benefit. — The curious will 

 meet with gratification relative to this fubjeft, by con- 

 futing Hill's Traft On the Sleep cf Plants ; or hi* 

 gardening for Oftober: — a large tolio. 



One of the offices of leaves, feems to be, te fubtilize* 

 and give more fpirit to the abundance of nourifhing 

 fap, and to convey it to the little buds at their foot Jlaik, 

 to whofe welfare they are -efTential. 



If the texture of the leaves be fcrutinized, they are 

 found cujrioufly ramified ; the ribs and fibres of each 

 - teeming much like a fpreading plant. The ramifica- 

 tions hold a clofe communication with each other; 



