COMPOSITION OF PLANTS 47 



same plant, to as great an extent as do the water and 

 di\ matter. Peas, beans and clover contain more pro- 

 tein than hay or straw. T of beans and peas 

 contain large quantities of protein, while the see 

 wheal and corn are made Dp principally of non-nitro- 

 •II- matters. 



43. Protein. — The DJtrogen-containing Bubstances 

 of plants are all compounds which are made up of five 

 elements- carbon, hydrogen, oxygen, nitrogen, And sul- 

 phur — with sometimes the addition of very small quan- 

 tities of another elem«-nt called phosphorus. The first 



laments are called the organic elements, 

 se they make up such a large part of all organic 

 matter. Their nanus are often abbreviated by writing 

 simply the first letter of the name, thus: (' for carbon, 

 II for hydrogen, <> for oxygen, N for nitrogen, and s 

 for sulphur. These five letters make a word. CHONS, 

 which may help one to remember how the nitrogenous 

 :• of plants is made up. There are a number of 

 different nitrogen compounds in mod plant-, hut they 

 are somewhat alike, and wc may properly call them by 

 one name, protein; just as we call the inhabitant 

 this country by one name, Americana. Albumen ma) be 

 mentioned as one of the moffi valuable compounds that 



ii. The white of an egg is pure albumen, 

 and is the he-t example of an ; lhuminoid. 



i of the organic elements, C, EL () . and X, were 



bed in Chapter III. The fifth element is 8UL- 

 riii i:. 



44. Sulphur. — Thil element ii a solid substance, and 

 is probably better known as brimstone. Sulphur is 



