OBSERVATIONS ON SOILS. 123 



free passage through it, and both are necessary ; and for plants 

 having strong roots, especially when large specimens are cultivated, 

 soil having a greater consistence is requisite. 



We shall now shortly notice soil in its nutritive qualities, or the 

 food of plants. The food of plants does not consist of anything solid, 

 such as earthy matter. Plants have not the power of absorbing any- 

 thing solid whatever. Their nutriment consists almost entirely in 

 water, — water is not a simple, but compound element, — and carbonic 

 acid ; the decay of organic matter combined with water forming 

 carbon. Hence the fertility of soils consists only in the abundance 

 of organic remains. We are thus led to see how vegetation, century 

 after century, luxuriates from the effects of her own partial decay ; 

 annually strewing around her the very elements necessary to her 

 existence and extension. This is information of the most valuable 

 description, and comes from a source which precludes the possibility 

 of error. From this we infer that a soil mechanically right, and 

 abounding naturally in organic remains, will abundantly answer all 

 ordinary purposes. 



But, as we have now so many plants, so to speak, artificially 

 improved so much beyond their natural parents that a more than 

 ordinary supply of the natural nutriment proper to them must be 

 provided, in order that they may be able to support and perfect their 

 extra developments, we need only mention the rose, the dahlia, the 

 dianthus tribe, &c. This provision we have in a comparatively 

 simple state in cow-dung; which is only vegetable substance sub- 

 jected to a more rapid change in the stomach than it does from 

 natural decay and atmospheric influence. This, however, in a recent 

 state is quite unfit for the roots of delicate plants, owing to the rapid 

 evolution of its gases; for these, although necessary to the existence 

 of the plant, are, in this case, given out in such abundance as to 

 gorge the absorbing rootlets, and cause a disarrangement in the 

 internal economy of the plant that is almost sure to end in death, or, 

 at all events, defeat the object in view, which we have presumed as 

 being flowers. Before we can safely use cow-dung in the cultivation 

 of the more delicate rooted plants, it must have undergone a con- 

 siderable degree of decomposition ; and in this state it still contains 

 a great proportion of the proper food of plants. The proportion of it 

 to be mixed in the soil must be in proportion to the nature and state 



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