On the Anatomy of Vegetables. 37 



acquiring a knowledge of the organs of that plant. I ufed 

 comparatively four or five different microfcopesj and, when 

 I fuppofed that I had got the whole feries of facls, I tried 

 the fame obfervations on a great number of other vegetables. 

 The eomparifons I then made greatly contributed to give me 

 information refpetting the nature and form of the organs ; 

 and to obviate, by every mean poliible, the illufions which 

 might lead me into a falfe path, I begged C. MafTey, my 

 friend and fellow-labourer, to revife my obfervations, and to 

 examine them with the fevered criticifm. Mis obfervations 

 compared with mine have either confirmed or rectified them. 

 I fhall now give a defcription of the parts which I call 

 elementary organs, becaule all the other organs are compofed 

 of them. 



Chap. I. 



Of thofe Parts which are dijlinguifhed by the naked Eye. 



Vegetables in general are compofed, as every body may 

 have obferved, of foft and hard parts. Some, indeed, fuch 

 as mufh rooms and fuci, feem to be formed entirely of a ho- 

 mogeneous Jubilance, pretty foft; but this clafs is not very 

 numerous. 



The ftem of the moft perfect plants prefents at its furface 

 a coloured fubftance of greater or lefs thicknefs, which is the 

 bark. Jt adheres ftrongly to the interior parts in a great many 

 of the monocotyledons, and fometimes even is confounded 

 and connected with them in fuch a manner that it is impof- 

 fible to diftinguifh them. It may in this cafe be laid that no 

 bark exills. This phenomenon is obferved in the palms, 

 gramineous plants, &c. But in the dicotyledons and fome 

 monocotyledons the bark, very ditlinct from the reft of the 

 tituie, forms an exterior ftratum, which may be eafily de- 

 tached. 



Below the bark is found the wood more compact, harder, 

 and more connected in all its parts, and which feems to be 

 formed of longitudinal fibres ftrongly cemented to each other. 

 In the monocotyledons without bark there is found, imme- 

 diately below the epidermis, a line tranfparent membrane, 

 which is the exterior part of the vegetable. 



The wood, as the learned Desfontaines has faid in his ex- 

 cellent memoir on the Comparative Anatomy of Vegetables, 

 is diitributed length wife in the ftem and branches of the 

 monocotyledons in delicate threads: thefe threads are often 

 parallel, and fometimes convergent one towards the other; 

 they unite one and one, two and two, or divide themfelves, 

 aucf become ramified in threads of ftill greater finenefs. AH 



C 3 thefq 



