150 From Matter to Man. 



leaves absorb carbonic acid gas by their cells and 

 through chemical action, by means of chlorophyll, 

 retain the carbon as starch, but reject the oxygen. 

 The starch is then digested in the vegetal organism 

 like food in the animal body. 



All plants contain about fifty per cent, of carbon in 

 their composition, but the vital constituent of every 

 plant, and the chief content of every cell, is protoplasm. 

 In some plants, if not in all, it maintains a constant 

 circulation throughout the organism, thus correspond- 

 ing to blood in the animal system. 



Protoplasm is a viscid granular matter composed of 

 carbon, hydrogen, oxygen, nitrogen, and sulphur, in 

 proportions not yet determined. Seen under the 

 microscope it exhibits spontaneous movement, waves 

 traverse its surface, threads and lobes project from it, 

 and ceaseless motions of all kinds distract it. Ex- 

 amined in minute pieces it reveals no regular shape, 

 no visible structure, no perceptible organisation, and 

 no apparatus for feeding. That it has a shape or 

 rather shapes is inevitable; that it has a structure though 

 unseen by us is indispensable to its existence as com- 

 pound substance ; that it has an organisation, however 

 elementary, is obvious from its motion, irresponsible 

 and ungoverned as it seemingly is ; and that it feeds 

 or performs some chemical action equivalent to 

 feeding is incumbent on it as a body endowed with 

 life. 



Circulation of water occurs throughout plants, for 

 they transpire, or part with water through pores in 



