228 



THE MICROSCOPE. 



Cell Changes. We now find the cell changing in its 

 outward form, and the transparent membranous cell wall 

 becoming thickened ; spontaneous fissure takes place, and 

 thus is formed a series of connected cells variously modi- 

 fied and arranged, according to the conditions under which 



b 



Fig. 130. a, elementary cells ; b, branched cellular tissue. 



they are developed and the functions which they are 

 destined to exercise. The typical form, as we have before 

 observed, of the vegetable cell is spheroidal ; but when 

 developed under pressure within walls, or denser tissues, 

 it takes other shapes ; as the 

 oblong, lobed, square, prisma- 

 tical, cylindrical, fusiform, muri- 

 form, stellate, filamentous, &c. : 

 and is then termed Parenchym, 

 and the cells woven together 

 are called cellular tissue. In 

 pulpy fruits the cells may be 

 easily separated one from the 

 other : a thin transverse section 

 of a strawberry is represented 

 atfig.!45,No. 15: within the cells 

 are smaller cells, commonly 

 known as pulp. Fig. 130, a, is 

 the elementary form of oval 

 Fig. isi. cells or vesicles, passing on to 



j, A transverse section of stem of fa Q formation of branched cel- 



qutsetum, showing the hexago- , 7 T> i i i 



nai shape of ceils. 2, A vertical lular tissue, 6. .Remarkable 

 section of elongated cell. specimens of the filamentous 



tissue may be seen in fig. 145, No. 19, the fungiform elon- 

 gated cells from the Mushroom; only another and more 

 closely connected growth of mucedinous fungi, commonly 

 called mushroom spawn. 



