■^ Researches respecting the 



43 a base, is nothing else than the junction of the exterior 

 sides*'." 



The observations even of Saussure seem to confirm my 

 opinion in regard to the non-existence of the epidermis, 

 since he expresses himself in this manner f : — " The system 

 of the vessels which constitutes the bark of the leaves, and 

 which touches on the one hand the parcuchyme and the 

 ribs of the leaves, and on the other the epidermis properly 

 so called — this svstem of vessels generally adheres to its 

 epidermis much stronger thm to any thing else. It, how- 

 ever, sometimes happens that a part of the reticulation re- 

 mains adhering to the parenchyme of the barU ; but this is 

 very rare. Continued maceration in cold or l)oiling w\atcr 

 till the leaf is dissolved, separates very rarely the cortical 

 reticulation from its epidermis. I never saw this separation 

 take place but in the sonckus spinosus." 



May it not thence be inferred that this author was never 

 able to separate the epidermis without removing w ith it the 

 vessels, except in the leaves of the sonchus ? This appears 

 to me evident. But if I have always found in this' fine pel- 

 licle the utricular organization, and if I am al>le to prove 

 that the vessels of its cortical reticulation are nothing else 

 than the lateral faces of the exterior utricuk«, may 1 not 

 reasonably conclude that this epidermis is merely the ex- 

 ternal face of the exterior utricul* ? 



The cortical reticuLaiion of Savissure, covered by the epi- 

 dermis, is composed of iibres or filaments, w hich by ana- 

 stomosing form the meshes of this reticulation, and tin-, form 

 of these meshes varies according to the ditfcrent plants. 



This author says % : " In all the leaves which I ha\ t ob- 

 served, four, five, six, and even seven filaments terminate 

 at one and the same mesh : though six be the most frequent 

 number, it does not thence follow that these meshes are re- 

 gular hexagons; for the fibres which compose this reticula- 

 tion are subject to such frequent inflections, and proceed 

 winding in so irregular a serpentine manner, that in the 

 greater number of species the nteshes have no regular or 

 constant form. The filaments which conipose these nieshes 



• In my opinion, C. Mirbc! is mistaken when h'j applies '.o t>e epi- 

 dermis of Jeavcs what Malpighi s^iil lespcctiag the epidermis of trei-i, 

 naiDciy, tliat it ij forroec! bv the desiccation ot the utriculjc. M?lpithi 

 expresses hLinsctf in rcgaid to leaves as follows, p. j; : '• Tori exnr:i- 

 torum moles qui'nus tolii coagmcntmitur, l.Evi supercxf.nsa c^iticiila .seu 

 cpi^krnitdc abd'tcitur, <]uj{ subjcctorum ccloren> rtftrt, ipsaqus contenra 

 cUstocHt et cor.rinet." 



t Page 40 and 41. i Page 32 et ssq. 



app^.-ar 



