162 ACTION OF SOIL ON FOOD OF PLANTS IN MANURE. 



way to explain the strange behaviour of the clover-plant 

 upon the two fields, they do not hesitate to present the 

 farmer with the following ingenious explanation : 



' Among plants,' say they, ' there are certain kinds 

 which are peculiarly circumstanced with respect to the 

 nature of their food ; the cereals, among others, feed 

 principally upon inorganic matters, whilst others, the 

 leguminous plants, e. g. clover, are dependent for luxu- 

 riant growth, more or less, upon a supply within the 

 soil of complex organic compounds.' 



Taking their stand upon the fact that they have 

 failed to discover any explanation, which, in their 

 opinion, they surely must have done, had it been pos- 

 sible to find one, they coolly ask us to believe that 

 there are, among the higher classes of plants, certain 

 species bearing about the same relation to other species 

 as the carnivorous to the graminivorous animals ; and 

 as the former feed upon complex organic compounds 

 prepared in the bodies of the latter, so it is, also, with 

 the clover-plant ; like mushrooms, it represents the car- 

 nivorous order in the vegetable kingdom. 



It is hardly worth while to take any notice of this 

 explanation ; but it might still prove useful to inquire 

 whether, apart from all consideration of the absorptive 

 power of the soil, Messrs. Lawes and Gilbert have really 

 exhausted all the means that might have been employed 

 to restore the productiveness of the clover-sick field for 

 clover, so as to be justified in giving it as their opinion 

 that when land is clover-sick, none of the ordinary ma- 

 nures, artificial or natural, can be relied upon to secure 

 a crop. 



We may ask why Messrs. Lawes and Gilbert did 

 not, instead of superphosphate of lime, try bone ash, 

 the action of which extends much deeper than that of 

 the superphosphate ; and why sulphate of potash and 

 sulphates alone were employed ? It is not impossible 

 that common wood ashes might have proved more 

 effective than sulphate of potash ; and, above all, chlo- 

 ride of potassium ought to have been tried, which, as 

 an ingredient of liquid manure, is more useful to clover 



