CHAPTER II 

 CELLULAR ORGANIZATION OF LIFE 



Science never destroys wonder, but only shifts it, higher and 

 deeper. — Thomson. 



With a synoptic view of the scope and importance of biology 

 before us, we now turn directly to the study of life itself in the 

 only form it is known — the bodies of plants and animals. 



A thin slice of material from the surface of the skin of a Frog 

 or the leaf of a Buttercup when examined under the microscope 

 shows the same general structure. Each appears to be composed 

 of innumerable small bodies, no two of which are exactly alike 

 even in the same piece, though all are similar enough to be one and 



A B 



Fig. 2. — Cells, highly magnifled, from the surface of a Frog's skin (A), 



and a plant leaf (B). 



the same type of unit. And if we extend our study to other parts 

 of the Buttercup or the Frog or, indeed, to any part of any familiar 

 plant or animal — or to the human body — we find essentially 

 similar units of structure in every case. In fact, the bodies of all 

 living things either consist of a single organic unit or of millions 

 of essentially similar units called cells. (Figs. 2, 3, 4.) 



Each cell is itself the theater of all the fundamental vital proc- 

 esses — each is alive. This, of course, is obvious when a cell forms 

 the whole body of a unicellular plant or animal, but not so 

 apparent when it is only one of myriads forming a multicellular 

 organism. But actually the life of the organism as a whole is, in 



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