A TREATISE 



ON THE FORCES WHICH PRODUCE 



THE ORGANIZATION OF PLANTS. 



CHAPTER I. 



ON THE ACTION OF THE SUNBEAMS IN PRODUCING ORGANIZED BODIES. 



CONTENTS : The Growth of Conferva in Water. Production of Green Matter by Spun 

 Glass and Inorganic Bodies. It requires a Sporule, Cell, or Objective Germ. Mode 

 of Diffusion of Gases into Water. Influence of Temperature on the Process. Action 

 of the Sun's Rays on these Gases. Two Atmospheres around the Earth. Sources 

 of Supply of the expended Gases. 



Application of these Principles to the Production of Chlorophyl in Leaves. The Di- 

 gestion of Plants. 



40. IF we expose some spring water to the sunshine, though it may have been clear 

 and transparent at first, it presently begins to assume a greenish tint, and, after a while, 

 flocks of green matter collect on the sides of the vessel in which it is contained. On 

 these flocks, whenever the sun is shining, bubbles of gas may be seen, which, if collected, 

 prove to be a mixture of oxygen and nitrogen, the proportion of the two being variable. 

 Meantime the green matter rapidly grows, its new parts, as they are developed, being 

 all day long covered with air-bells, which disappear as soon as the sun is set. If these 

 observations be made on a stream of water, the current of which runs slowly, it will be 

 discovered that the green matter serves as food for thousands of aquatic insects, which 

 make their habitations in it. These insects are endued with powers of rapid locomo- 

 tion, and possess a highly-organized structure ; in their turn, they fall a prey to the 

 fishes which frequent such streams. Organic chemistry teaches that it is the office of 

 vegetable life to form from inorganic matter organized molecules, and furnish them as 

 food for the support of animals, which simply assimilate, but do not fabricate ; we must, 

 therefore, infer that the fibrine, the albumen, the gelatine, the fat, and whatever else of 

 those compound organic molecules is required for the support of fishes and insects, are 

 originally formed by the action of light on that green matter. But the production of this 

 substance is the result of a multitude of coincident actions. The sunlight is the agent 

 which directs its growth, but it does not so plainly appear what is the body from which 

 it originally springs, and on which the light exerts its influence ; whether it comes from 

 microscopic germs which, floating about in the air, find their way into every water, or 



