SPECIFIC FOOD IN SOILS FOR PLANTS. 299 



the stomach as to perforate its walls ; and this was 

 owing to ignorance of the distance between the 

 mouth and the stomach. If regard to the sufferings 

 of the animal does not influence them, the fact that 

 such cruel treatment must be a source of loss should 

 induce farmers to adopt a better and more scientific 

 mode of treatment. 



SPECIFIC FOOD IN SOILS FOR PLANTS. 



That soils the most favourable for the growth of 

 plants of any particular kind may, unless attention 

 is paid to furnishing a supply of the food in which 

 such plants delight, become exhausted and unfit for 

 their production, is a fact which a multitude of ex- 

 periments fully proves, and which seems to be gen- 

 erally admitted. The earths themselves, silex, lime, 

 and clay, can hardly be said to be the food of plants, 

 though minute portions of them are taken up by the 

 ^ssels and appropriated to the structure of the 

 firmer parts. The earths seem only to serve as a 

 reservoir for the nutritive matter; or perhaps they 

 constitute rather the fountain of that electro-mag- 

 netic agency which has been proved so efficient, if 

 not, indeed, the sole cause of vegetation. 



We may reduce plants to their elements by cal- 

 cination, and we may examine the products given 

 by their decomposition, but we only discover the 

 parts that are left: the power that collected their 

 particles has ceased to operate ; and we should be 

 almost as well qualified to judge of what the human 

 lody can perform, and of the nature of its nutrition 

 and growth, from a post mortem examination, as to 

 decide on these same functions in a living plant 

 from an examination of the remains of a dead one. 

 Chymistry has performed wonders, and from its in- 

 valuable aid much more may be expected ; but the 

 causes that change the qualities of a soil, and, of 

 course, the whole character of its vegetation, are of 

 such a nature, and, perhaps, so slight or evanescent, 



