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WATBIDB WEBDS. 



you must take on trust the fact tliat vegetable 

 structure generally is made up of cells and vessels ; 

 or, if the latter he regarded merely as elongated 

 cells, it may be said, even of the forest tree, that it 

 is simply an aggregation of innumerable vegetable 

 cells. However, the distinction into cell, and into 

 fibre and vessel is more appropriate and con- 

 venient. The lowest tribes of pjants, such as the 

 seaweeds, the mosses, and the fongi or mushrooms, 

 are really and truly made up of cells only. But we 

 are talking of cells, when, perhaps, simple as the 

 thing is in itself, few of our readers have formed 

 any idea upon the subject. A cell is a very minute 



Fig. 100,— Vegetable tissue magnified, shoving cells and spiral Tessels. 



bag or vesicle, with very thin walls of vegetable 

 tissue ; thin comparatively, but varying in the thick- 

 ness of their walls considerably among themselves. 

 These minute httle cells differ much in shape, 

 being round, oval, six sided, etc., and fitting closely to 

 one another, or leaving interstices, or " intercellular 

 spaces " between. Moreover, cells may be flattened, 

 as we shall see in the cuticle or skin of the plant. Or 

 they may be elongated more or less, when they 

 become vessels or fibres ; and as there are varieties 



