404 THE UNIVERSE. 



whicli swells out their tissues. Among these "heralds of 

 ruined soils," as Ch. Mliller calls them, the roots, repre- 

 sented only by a fe^y dried fibres, draAV absolutely nothing 

 from the calcined rock which supports them. It is there- 

 fore the stem which nourishes itself; the leaves are so 

 rudimentary, so little apparent, that it may be looked upon 

 as entirely deprived of them. 



In our hot-houses the same thing may be seen every 

 day. Cactuses, which are never watered, thrive there 

 splendidly by means of the moist and warm atmosphere 

 with which they are surrounded. 



CHAPTEE II. 



THE CIRCULATION IN PLANTS. 



The more we study nature the grander does she appear. 

 Science, by penetrating her secrets, often shows us that 

 hidden and imposing forces exist where we only see inertia. 

 The obscure vitality of plants, brought to light by the 

 genius of naturalists, sometimes manifests itself to our eyes 

 in unexpected power. 



Plants, like animals, have a circulation. It is to that 

 universal genius Claude Perrault, at one and the same 

 time physician, architect, and naturalist, that we owe the 

 discovery of this phenomenon. The sap, which is in fact 

 the blood of the plant, circulates through its vessels by 

 means of a power possibly greatly exceeding that which 

 drives the blood through the arteries of an elephant. The 



