VEGETABLE ORGANIZATION. 



67 



that from 3,000 to 100,000 cells would be con- 

 tained in an extent of surface equal to a square 

 inch. But they are occasionally met with of dif- 

 ferent sizes, from even the 1000th part of an 

 inch to the 30th. 



In their original state, these vesicles have 

 an oval or globular form ; but they are soon 

 transformed into other shapes, either by the 

 mutual compression which they sustain from 

 being crowded into a limited space, or from 

 unequal expansions in the progress of their 

 developement. From the first of these causes 

 they often acquire angles, assuming the forms of 

 irregular rhomboidal dodecahedrons, and often 

 of hexagonal prisms, like the cells of a honey- 

 comb ; arid by the second, they are elongated 



