THE 



CHEMISTRY OF THE FARM. 



CHAPTER I. 



PLANT GROWTH. 



The Co7istitiie7its of Plants. — Water — The combustible elements of 

 vegetable matter — The proportion of ash constituents in various 

 parts of plants— The essential and non-essential elements of the 

 ash — Composition of a crop of grass. Funztion of tJie Leaves.— 

 Assimilation of carbon from the air — Formation of vegetable 

 substance — Plant respiration — The transpiration of water. Func- 

 tion of the Boots. — Absorption of ash constituents from-the soil — 

 The selective power of plants— Absorption of nitrogenous matter. 

 Co-operative Nutrition.— Hoot fungi— The organisms of leguminous 

 tubercles. Destination of Ash Constituents. — History of essential 

 and non-essential ash constituents — Variations in ash due to soil, 

 manure, and season — Composition of typical ashes. Germination. 

 — General structure of seeds — The conditions and processes of their 

 germination. Plant Development. — Annual plants — The order in 

 which plant constituents are assimilated — Exhaustion of roots 

 and stem during formation of seed — Biennial and perennial 

 plants — The storing up of food for a second season— Spring sap 

 rich in sugar. 



The first step towards a knowledge of plant chemistry 

 must be an acquaintance with the materials of which 

 plants are built up. 



The Constituents of Plants.— The most abundant 

 ingredient of a Hving plant is water. Many succulent 

 vegetables, as turnips and lettuce, contain more than 

 90 per cent, of water. Timber felled in the driest time 

 seldom contains less than 40 per cent, of water, 

 i 



