The Profound Effect on the Structure of Plants 



49 



ton such as animals must have, and permits a simply continuous 

 structure. This is why plants are sedentary beings, rooted for life 

 in one spot. 



Second. The four essentials circulate in no definite paths or 

 directions, hut come to the plant from every point of the compass. 

 This is true even of sunlight, despite the regular path of the sun 

 through the heavens, for so uniform is the diffusion of the light 

 through the sky that plants really receive it from every direction. 

 And as to the wind, does it not blow where it listeth, and the 

 waters, do they not cover the earth? Therefore plants have no 

 need to face their parts in any particular direction, as animals 

 must do in connection with their movements in search of their 

 food, but face evenly outward in every direction, thus requiring a 

 symmetrical distribution of their parts around a central vertical 

 axis. This is why plants are radially built, presenting the same 

 face to all points of the compass. 



Third. The four essentials are not evenly commingled, but seg- 

 regated into two strata, — the light and carbon dioxide in the at- 

 mosphere above, and the water and minerals in the soil under- 

 neath. Therefore plants must needs have two parts to their 

 structure adapted to life in these two very different situations. 

 This is why plants exhibit their primary division of structure into 

 the green shoot (leaf and stem), and colorless root. 



Fourth. The four essentials exist rarely in abundance and then 

 never for much of the time, and most commonly are sparser than 

 plants can make use of. Frequently the light, always the carbon 

 dioxide, often the water, and sometimes the minerals are accessi- 

 ble only in dilution. Therefore the plant must needs reach out 

 extensiveh^ to come into contact with a sufficiency, — a condition in 

 great contrast to that prevailing in animals with their concen- 

 trated food and consequent compactness of body. This is why 

 plants are branched so profusely and slenderly. 



Fifth. One of the four essentials, — viz., light, is of such nature 

 that it cannot be transmitted far into the plant, and therefore must be 



