THE IMPROVEMENT OF SOILS. 



45 



at times the shape of its nest to adapt it to peculiar 

 surroundings, and so the farmer must use his reason 

 in cultivating his crop. He should be guided, not 

 by " cast-iron " rules, but by correct principles, and 

 modify his mode of cultivation to suit each particu- 

 lar case. 



CHAPTER VI. 



THE IMPROVEMENT OF SOILS. 



96. DEAD matter has no power in itself, so far as 

 we know, to change into an organized structure. It 

 has the power, under certain circumstances, of form- 

 ing crystals of great beauty, but in these forms there 

 is no life. This life-principle, every seed or germ 

 has within itself, and when called into activity it un- 

 folds the plant. Exactly what this life-principle is, 

 we know not, but we can study the conditions of 

 plant-growth, and explain to some extent the changes 

 which take place in the swelling of the seed by heat 

 and moisture, and its partial decomposition into 

 simpler forms, whereby energy is imparted in some 

 mysterious way, sufficient to push the rootlet down- 

 ward, and the slender stem upward to the sunlight. 



97. The connection between the rays of the sun 

 drunk in by the leaves of plants and the absorption 

 of food by their roots, the appropriation of this food 

 and its assimilation or use in the production of bark, 

 and wood, and leaves, and fruit, has not yet been ex- 



