Foods for Plants. .241 



soluble matter as possible to the roots of the 

 plants, and that in a slow and gradual manner, 

 so that it may be entirely consumed in forming 

 their soft and organized parts." 



Substances composed for the most part of 

 mucilage and gelatinous or fatty fluid, contain 

 nearly all the elements of life in vegetation ; but, 

 as these are always combined with masses of woody 

 fibre, a chemical change is necessary to render such 

 substances Suitable for food for plants. This change 

 is produced by decomposition. Animal matters 

 decompose more quickly than vegetable, and those 

 which are glutinous and albuminous more quickly 

 than woody fibre. Some manures, such as those 

 consisting principally of matter soluble in water, 

 decompose too rapidly, and this has then to be 

 prevented ; it being borne in mind that decomposi- 

 tion is only required to bring about a separation 

 between the organic constituents and the woody 

 fibre with which they are combined. 



Undue decomposition may be prevented in 

 manures by keeping them dry and cool, and by 

 protecting them from the atmosphere : while the 

 opposite result may be promoted by moisture and 

 a warm temperature (from 55 to 80). 



Liebig's opinion that the true theory of manuring 

 consisted in adding to the soil the constituents of 

 the ash of the plant, is now generally discredited, 



R 



