50 VEGETABLE ORGANOGRAPHY. 



scope. As early as 1813, I proposed, in the Theorie 

 Elementaire, to give to the tissue the names of dotted 

 (ponctue) and striped (raye), instead of those of porous 

 {poreux) and sKt {fendu), which Mirbel had established : 

 my intention was not to affirm any thing in addition to 

 what is proved ; and these names have in fact the advan- 

 tage of being admissible under all theories. More lately, 

 Dutrochet has given new proofs of the non-perforation 

 of the dots and lines : he considers the dots to be little 

 globular bodies filled with a greenish transparent matter ; 

 he has observed that they become opaque by nitric 

 acid, and that then their centre no longer transmits 

 light : he adds that caustic potass restores their trans- 

 parency, that there are certainly no visible pores, and 

 that the doctrine of Mirbel is doubtful from the sole fact 

 of the size which he has attributed to them. 



If we admit that the markings of vessels are not 

 perforated bodies, we must seek farther in order to 

 discover their nature. Rudolphi and Link regard them 

 as amylaceous or mucilaginous granules. Treviranus 

 appears to consider them as young cellules, destined to 

 increase in size and to become themselves distinct cel- 

 lules. Dutrochet (considering that they undergo the 

 same changes mider the action of acids and alkalies as 

 the globules of the nervous system of animals — that is to 

 say, that they are insoluble in the first, and soluble in the 

 latter, knowing that the animals most nearly related to 

 plants have a nervous system always less concentrated, 

 and seeing that these markings exist in sufficiently great 

 abundance in the vegetable organs which perform any 

 movement,) has believed that they may be considered as 

 the widely spread elements of a diffuse nervous system ; 

 and he has proposed to call them nervous corpuscules 

 {corpuscules nerveux), meaning by this term a globular 

 microscopic cellule filled with nervous substance. 



