LINK ON CELLULAR TISSUE. 



may plainly distinguish the upper edge of the partition from the lower 

 edge ; and at the same time may.be observed the little interval, which 

 is usually filled with a dark matter, somewhat fluid. This is repre- 

 sented in the figure, (2) as taken from the stalk of the Cacaliajicoides. 



Fig. 2. 



M. Treviranus calls these intervals meatus intercellulares. They are 

 found only between the edges of the partition ; the rest of them ex- 

 hibit only a simple membrane. I find also other intervals between 

 these cells, which may be called Ductus intercellulares. They de- 

 scend in a perpendicular direction ; they have no visible communica- 

 tion with the intervals which I have just described, and they contain 

 a juice which is less fluid than the sap, and issues sometimes in the 

 form of small round corpuscules, and sometimes in the form of crys- 

 tals. These canals are considerably larger than the Meatus inter- 

 cellulares. These are represented in the figure (3), in a cross section 



Fig. 3. 



of the stalk of the Cnicus oleraceus, and in a longitudinal section of 

 the same stalk. They are found in many plants, particularly if the 

 tissue of cells is not very close, and they may be ranged among the 

 reservoirs of the pulp. 



In the ferns and mosses the intervals are so large, and so well 

 united together, that they perfectly resemble vessels. They form a, 



