CELLULAR TISSUE, 19 
third tissue, intermediate between these two, is generally 
_ added; so that there are three vegetable tissues to be de- 
-__ seribed. 
CELLuLaR Tissux, 
Woopy Tissvr, 
VascuLar Tissvus. 
42. Of these, though ultimately sufficiently distinct, cel- 
lular tissue is believed to be the origin or basis: it is the 
only tissue universally found in plants, and is often the only 
tissue in parts in which the other forms become afterwards 
developed ; as, for example, in seeds. 
L—CELLULAR TISSUE. 
45. The cellular tissue consists of a series of | sphere 
or short tubes—promiscuously termed s— ae 
ering to each other, formed of the thin, transpa- 
rent, and colourless vegetable membrane, and having occa- 
sionally fibre wound round their inner surface. Each cell 
is complete in itself, the wall or partition between two adjoin- 
ing cells being, therefore, formed originally of two layers of 
membrane, though sometimes incorporated in one Jager 
The partitions may often be separated by boiling the cells ee 
pith or soft pulpy fruits in water or in nitrie acid. As = 
already mentioned, under membrane, there are no visible 
pores in the sides of the cells, though there is no doubt that — 
they give passage to fluids. The function of the cellular” 
. tissue is to contain fluids, and: give: them: a. pemage Tig B 
2 directions. 
