VEGETABLE ORGANIZATION. 



61 



nerally adhere together more closely, composing by their 

 union a species of vegetable cellular tissue, which may be 

 regarded as the basis or essential component material of 

 every organ in the plant. This cellular structure is repre- 

 sented in figures 4 and 5, as it appears in the Fucus vesicu- 

 losus; the first being a horizontal, and the second a vertical 

 section of that plant.* The size of these cells differs consi- 

 derably in different instances. Kieser states that the dia- 

 meter of each individual cell varies from the 330th to the 

 55th part of an inch; so that from 3,000 to 100,000 cells 

 would be contained in an extent of surface equal to a square 

 inch. But they are occasionally met with of different sizes, 

 from even the 1000th part of an inch to the 30th. 



In their original state, these vesicles have an oval or glo- 

 bular 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 expan- 

 sions in the progress of their development. 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; and by 



Slack's memoir on the elementary tissue of plants, contained in the 49th vo- 

 lume of the Transactions of the Society of Arts. 

 * De Candollc, Org-anographie V^getale. 



