Peat-Mosses 



forced out through the holes on the opposite sides. When all 

 the large cells are filled with water, the contents of the small 

 cells can absorb through their thin walls the water from the 

 adjoining large cells. 



It may help one to comprehend the structure to imagine a 

 number of thin, transparent-glass capsules of irregular shape, 

 with spiral or circular thickenings of glass in their walls and tiny 

 openings here and there. Imagine the capsules piled up with 

 the openings of each capsule contiguous to the openings of 

 adjoining capsules and all the spaces between filled with very 

 small capsules containing a colourless jelly and green granules. 



Diagram to show plan of cell-structure. 



If the base of this imaginary pile be immersed in water, immedi- 

 ately the water will creep up through the whole system. This 

 is in accordance with nature's law that water rises in fine hair- 

 like tubes or crevices. To understand the process by which the 

 water passes from a large cell to a small cell one must recall 

 another of nature's laws, that whenever a non-crystallisable 

 substance, as the cell-contents of the small cells, is separated by 

 a membranous partition from a crystallisable liquid, as the water 

 in the large cells, the crystallisable liquid will pass through the 

 membranous wall into the non-crystallisable substance. 



It is evident that one function of the large cells is to procure 

 water for the small cells to work with ; but since this same 

 function would be performed as well if all the cells were filled 



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