THE GENERAL STRUCTURE 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 
Fic. 8,—FiGuRES OF DIFFERENT BacTertis4. (After Cohn and Sachs. 
Very highly magnified.) 
1, Sarcina; 2, Bacillus; 3, Spirillum; 4, Spirillum with flagella; 
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 ceil. 
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 
