CHEMICAL FERTILIZERS. 115 



reasonable. The roots of land plants are in direct contact with 

 the particles of the soil. A quantity of moisture, but no more 

 than the soil holds by attraction, is essential to growth. The soil 

 holds the elements of food, whether conveyed to it in fluid or other 

 form, and the solution of the solid elements is eflfected in the 

 pores of the cell walls of the roots, whence they pass into the sys- 

 tem of the plant. 



We know that stagnant water is injurious to land plants, and so 

 that only so much of the plant food as is not carried away b}' 

 watering is beneficial. 



That the elements of fertility, such, for instance, as potash, may 

 be washed out of a soil in which they abound, as potash is washed 

 out of ashes, is well known, but it does not follow that the soil, if 

 of a fertile character, does not retain as much of these elements as is 

 good for the plant. If this is not so, why, in the daily watering of 

 plants in pots, is not all the fertilitj' washed out of the soil, so that 

 the plant should require daily fertilizing as well as watering. 



Liebig cites, in support of his theory, the beautiful experiments 

 by Professor Nageli and Dr. Zoeller, in the Botanic Garden at 

 Munich, in which they grew these plants successfully in a soil con- 

 taining all the elements of their food in an insoluble state. It may 

 be interesting to observe that these experiments were conducted 

 with the three elements and those only, which Prof. Stockbridge 

 uses in his fertilizers, namely, nitrogen, potash, and phosphoric 

 acid, * Indeed Liebig ascribes to the soil itself a power which 

 seems to override and control the chemical combinations by which 

 we endeavor to accommodate what we deem to be the wants of the 

 plants. " The arable soil," he says,f " decomposes all salts of 

 potash, of ammonia, and the soluble phosphates ; and the potash, 

 ammonia, and phosphoric acid always take the same form in the 

 soil, no matter from what salt they are derived." 



He maintains, as we have said, that plants are by no means 

 limited to such elements as are soluble in water, but that they 

 "possess the power of absorbing theirnecessary nutritive elements 

 from a soil in which they are present in physical combination, i. e., 

 in a state wherein they have lost their solubility in water." J In 

 proof of this, he says a rye plant will yield a thousand fold in a 

 fertile soil, "yet this plant draws its mineral food from a volume 



♦Natural Laws of Husbandry, page 114. f Ibid, p. 119. J Ibid, p. 118. 



