450 Dr. Willshire on some points of Vegetable Structure. 



to the phaenomena shown to exist in animal blood. These ob- 

 jects were formerly looked upon from their peculiarity of shape 

 as crystals ; but Hartig (Erdman's and Schweiggerseidel's 

 Journal, 1835) stated they were formed of amylum; and Meyen 

 (ut antea) regarded the stripes or lines as caused by tearings 

 or lacerations of the inner portion of the substance of the amy- 

 laceous body by a gradual extension of its layers. 



Whatever may be the peculiar forms however of these bo- 

 dies, and admitting their identity of reaction as regards iodine 

 with that of starchy material, we conceive that, so far from re- 

 garding them as not the absolute essentials of the lactiferous 

 fluid, and as not analogous to those of the blood, the present 

 state of our knowledge allows us to consider them as actually 

 the same, and as forming mediate generative structural mat- 

 ter for vegetable tissue, since it has been shown by Mohl (Va- 

 lentin's Repert., 1841) that colour varying from brown to blue 

 may be produced in all vegetable membranes under certain 

 conditions by iodine ; and by Payen (Valentin's Repert. and 

 Comptes Rendus) that the substance which forms the ele- 

 mentary structure of all plants is the same in all species, that 

 this primary substance is cellulosa, that it alone forms the 

 walls of earliest formed tissue, that it can be converted into 

 dextrine by the action of sulphuric acid, and that it has with 

 amidon a similarity of composition. To look therefore upon 

 these bodies as mere crystals or as pieces of starch, we think 

 now unwarranted, and they should be considered as primordial 

 bodies of cellulosa ; the dark lines or stripes being probably 

 filaments or fibres, and the whole being analogous to the cor- 

 puscle of the blood with its filament or fibre, and which serves 

 to produce new tissue. We confess, in our present state of 

 knowledge with respect to vegetable anatomy, we cannot lay 

 down as a rule, that fibre or filament is always the primary 

 form of evolution; and we consider that, without assuming that 

 for which we have no ocular proof, we must yet rest satisfied 

 with believing that much tissue is not derivable from fibre. 

 Yet that it often is, and primarily so, may be allowed ; and 

 every vegetable physiologist will have met with abundance of 

 proof, that what, under less careful investigation, or merely 

 ordinary circumstances, has appeared primary homogeneous 

 membrane, has, with more care and delicate investigation, been 

 resolvable into fibre or filament, primary and elementary. Al- 

 though in many plants the parietes of lactiferous tissue are 

 homogeneous, showing no trace of fibre, yet in Euphorbia 

 magnispina they are resolvable into spiral filaments, which we 

 are not inclined to believe are of secondary origin in these 

 ducts, but of primary. Further, though there is abundance 



