LIFE ON THE FAKM 



PLANT LIFE. 



CHAPTER L 



PLANT-NUTRITION: THE WORK AND THE MATERIALS. 



Introductory remarks. What plants do and how they do it. Receipts. 

 Expenditure. Accumulation. Transformation. How plants feed. 

 Influence of temperature. Water and the machinery by which it is 

 supplied and distributed. Protoplasm. Cells and their contents. 

 Ingress and movements of water. The first stage of nutrition. Diffu- 

 sion. Osmosis and the requisite conditions forit. Saturation. Vary- 

 ing degrees of, according to the nature of the liquid. Amount absorbed. 

 Supply and demand. Differences of composition of plants grown in 

 the same soil, how explained. Continuous change. Nutritive value 

 of water. Nitrates; agency of Bacteria. Potash. Sulphur. Phos- 

 phorus. Iron. Lime. Principles of manuring. Power of 

 selection. 



HE who can make two blades of grass grow where only 

 one grew before is universally looked on as a benefactor to his 

 kind. No one will dispute his title to our gratitude ; but 

 at the same time it must not be overlooked that the claims 

 of him who can make one grow where none at all existed 

 before are even greater, because the difficulties to be over- 

 come are more formidable, for where one exists already it 

 is relatively easy to bring about its increase. 



In any case, it is clear that, before either problem can 



