116 M. L. Garreau on the Functions of 



been restricted to only that portion of it whicli enters into the 

 formation of the nucleus and of the canals and contractile fila- 

 ments ; however, in many plants, and among others in the epi- 

 dermic cells of young Arums, in the hairs of Umbelliferse and of 

 Boraginacese, in the epidermic cells of the leaves of Scolopen- 

 driiim officinarum vel undulatum, the azotized or living material 

 loses the characters detailed, and is represented only by filaments 

 which emerge from a semifluid mass and stretch themselves 

 towards the primordial membrane, exhibiting changes of position 

 very slowly, and impressing some movement on the fluid bathing 

 them. It is a fact that most physiologists who have interested 

 themselves in the rotary movement which occurs in the cells of 

 Char a attribute it to other causes; but in our opinion there is only 

 one true explanation of it, as pointed out by Schleiden, Hassall, 

 and Hugo Mohl, who have rightly perceived its mechanism, and 

 attributed it to the dense fluid which occupies the inner wall of 

 the cell-cavity. Dutrochet and Donne have inspected its cause 

 in the nearly mature merithalli of plants, — the first-named in the 

 course of attempts to suspend its course by means of poisonous 

 agents, and the second in recognizing the spontaneous move- 

 ments of detached and vermiform fragments of the primordial 

 membrane. Nevertheless these naturalists seem to assign an 

 influence to the green globules which they do not possess; for 

 these chlorophyl-granules are scarcely apparent in the very young 

 ramifications of Nitella flexilis, and are entirely absent in the 

 cortical cells of the rhizomes of Chara. Nevertheless the circu- 

 lation is very much more active in those parts than in merithalli 

 of greater maturity, wherein the green globules more abound. 

 They, in fact, contain a nitrogenous plastic material, filled with 

 excessively minute molecules, which creeps along the wall of the 

 tube, and impresses upon the aqueous liquid in contact with it, 

 and loaded with globules, a similar movement. What proves 

 that such is the cause of the motion in young cells is, that 

 though this nitrogenous matter be more dense than the fluid 

 with which it is bathed, it raises itself and moves along the tube 

 contrary to the action of gravity, and advances with incompa- 

 rably greater velocity than that of the fluid which accompanies 

 it in its course. In proportion as the merithalli are developed, 

 this matter gets fixed to the primordial membrane, in the forma- 

 tion of which, indeed, it takes part, and which, though adherent 

 to the cell-wall, propels onward the enclosed liquid of the cell, 

 not, as has been suspected, by the aid of vibratile cilia, but by 

 tolerably rapid undulations similar to those produced on the sur- 

 face of water ruffled by a gentle breeze. 



If, instead of limiting the examination of the vital movements 

 of the nitrogenous matter in the interior of the cells of phanero- 



