108 Researches respecting the 



idea of it. Saussurc expresses himself as follows : — " Tit 

 observing the cortical reticulation I have often had occasion 

 to study another reticulation which is placed immediately 

 below the former; it is the parenchymatous reticulation. 

 This reticulation' has larger and straighter vessels, and its 

 meshes arc generally greater than those of the cortical reti- 

 culation. The vessels of the parcnchyme are besides almost 

 always coloured, and for the most part green. They are 

 very rarely cylindric; in general they grow narrower and 

 larger in succession, so that they resemble vessels conti- 

 guous to each other." 



j-jedwig says * that he has seen in the leaves of moss 

 small ducts, di>^posed according to the length of the leaf, 

 which anastomose laterally with other transverse or lateral 

 ducts in such a manner as to form areolae sometimes square 

 and sometimes oblong, pentagonal, or hexagonal, which 

 almost all contain a parenclu'mc, the form of which is glo- 

 bular, and which gives to leaves their colour. 



Scnebier gives his opinion in the following terms f : — 

 The appellations of cellular tissue, cellular covering, and 

 parenchyme, are given indiflerently to that reticulation 

 formed by transparent fibres or vessels filled with a green 

 juice, which are anastomosed at the places where they meet, 

 and swelled up in the intervals. Utriculi will in all pro- 

 bability be found there, though nothing is seen with the 

 best glasses but the meshes of a reticulation. If we con- 

 ceive some parts of vegetables composed of fibres, forming 

 meshes with a sTranulaied substance, we shall have some 

 idea of the matter which constitutes the greater part of 

 leaves and fruits. The parenchyme I am about to describe 

 will be found in that in particular which fills up the 

 meshes of the greater part of reticulations. 



C. Mivbel considers the parenchyme of leaves as a cel- 

 lular tissue formed of cells which are filled with a juice 

 almost always coloured green. It does not consist, he says, 

 of small bags or utriculi ; it is a membrane which un- 

 lines itself in some measure to form vacuities contiguous 

 to each other. 



In all the leaves which I have examined I have always 

 found that their parenchyme was composed only of an ag- 

 gregation of utxiculi closciy united to each other, filled with 

 a green juice by which the)' are coloured, and of which the 

 form varies according to the difierent plants. For exam- 



* Miisci Frondosi, pars i. p. 24. 



t i*hy iiologie \"egctale, torn. i. p. i6i. 



plc. 



I 



