THE GENEEAL STEUCTURE OF PLANTS 3 



these masses of protoplasm, or cells, may be as small as 

 two, or may be enormous, as is the case in such plants as 

 the gigantic seaweeds of the tropics or the tall terrestrial 

 trees which abound all over the surface of the globe. 



Whether the plant is simple or complex, we find the 

 same fundamental arrangement of its parts : there is a 

 certain number of protoplasts, in close relationship with 

 each other, supported upon a framework or skeleton which 

 shows a wonderful variety of arrangement, its details 

 depending on the manner of life of the whole organism of 

 which it forms so large a part. In such an organism each 



FIG. 3. FIGUBES OF DIFFERENT BACTERIA. (After Cohn and Sachs. 

 Very highly magnified.) 



1, Sarcina ; 2, Bacillus ; 3, Spirillum ; 4, Spirillum with flagellee ; 

 5, 6, 7, Micrococcus. (Single, in strings, and in groups.) 



protoplast is usually found occupying a particular cavity 

 which is formed by its cell-walls, and communicating with 

 its neighbours on all sides' by delicate prolongations of 

 living substance which extend through the walls of con- 

 tiguous chambers. Each chamber is often called a cell. 



In dealing with the physiology of the plant, it is the 

 living substance which should first engage our attention, 

 though the arrangements of the supporting structures or 

 skeleton exhibit the greatest variety. We have seen that 

 in the simplest forms of plants the living substance may 

 exist without any cell-membrane, and may be freely motile, 

 swimming in water by means of cilia. The absence of the 



