226 On the Anatomy of Vegetables* 



they become ligneous are deflitute of them. Tiiefe pores ferve 

 for the fenfible and infenfibie tranfpiration and for the ab- 

 forption of the fluids. They each correfpond to a fmall cell, 

 which, according as the air is moifter than the cellular tiffue, 

 or the cellular tifiiie than the air, abforbs the fluids difperfed 

 throughout the atmofphere, or throws oifthofc which the ve- 

 getable contains. When the parts become ft iff, and the li- 

 quors contained in the vegetable have no longer the fame 

 fluidity, thefe cells become filled with thick gum and refill ; 

 which not being able to efcape through the pores, nor to re- 

 turn into general circulation, become entirely hard; and are 

 at length thrown out, when the ftate of the vegetable, by not 

 permitting the epidermis to dilate itfelf further, forces it to 

 burft. 



3d, The glandular pores. — Thefe are apertures bordered 

 with thick opake and unequal rolls. Thefe pores ferve for the 

 movement and communication of the fluids in the interior of 

 the vegetable. They are obferved fometimes indeed in the 

 epidermis, but this cafe is exceedingly rare. There are two 

 kinds of glandular pores, the fmall and the large. The former 

 are exceffively fmall. To the mod powerful microfcopes they 

 appear only like the fmall holes made in a fhect of paper with 

 the point of a needle: fometimes they are fcattered, and few in 

 number; at other times they are very numerous, anddifpofed 

 in regular feries, always according to the breadth, and never ac- 

 cording to the length of the tifluc. The large glandular pores- 

 are only a modification of them : one might even fuppofe that 

 the union of the fmall pores of one feries produces the large 

 ones, the direction of which is the fame as that of the feries. 

 The reader muft here call to mind what Lhave already faid 

 of the porous tubes, the falfe tracheae, and even the tracheae. 

 There are fome very linking relations between thefe different 

 tubes, and the plan of nature is not equivocal. 



Chap. VIII. 

 Of the Epidermis. 



This name is given to the exterior membrane formed by 

 fides of the outer cells ; or rather the epidermis is only the 

 term of the cellular thTue itfelf. 



To relate every thing that authors have faid on tins mem- 

 brane, would fill a volume. No part in the organization of 

 plants has given rife to more refearches, nor perhaps has led 

 into more errors. The fir ft fault is, to ^ have compared it 

 without reftriclion to the epidermis of animals. When this 

 idea was once adopted, every thing elfe was oohfidered as 

 analogous. The epidermis, faid fome writers, exifts in all or- 

 r ganized 



