MARVELS OF A PLANT'S GROWTH, 

 AND THE CHEMISTRY OF DECAY 1 



EY PKOFESSOB VIVIAN B. LEWES 



IN the whole of Nature's wonder book there is nothing 

 that appeals more to our sense of the marvelous than the 

 way in which all the waste of animal and vegetable life is 

 converted by decay into those simple compounds, carbon 

 dioxide and water vapor, which are again used in the 

 wonderful processes by which all forms of life are synthet- 

 ically recreated. 



It is the sun's rays which are the mainspring of this 

 regeneration, and the growth of vegetation is the means by 

 which it is brought about. All the ordinary forms of 

 plant in which the green pigment known as "chlorophyl" 

 is present, owe their growth to energy derived from the 

 sun, under which the chlorophyl contained in the small 

 glands of the plant absorbs carbon dioxide and water vapor 

 from the atmosphere, while more moisture and traces of 

 mineral salts are drawn in by the roots. Once absorbed 

 the carbon dioxide and water vapor under the influence of 

 the chlorophyl commence a marvelous series of changes, 

 which result in the formation of the first visible product, 

 the starch granules and also sugars, which afterward be- 

 come practically the food of the plant, and are incorporated 

 as the cellulose or woody fiber, of which the solid portion 

 chiefly consists, the completed reaction being of some such 

 nature as that expressed by the equation 



Carbon dioxide + Water vapor I +Sun , g energy i CeHn- Oxy. 



I CoHio 5 +60 2 



And it is this oxygen so liberated in the early days of the 



^Journal of the Society of Arts, abstracted in Scientific American 

 Supplement. 



103 



