SEEDS: THEIR PRESERVATION AND GERMINATION-. 649 



Seeds vary almost infinitely in their form and construction as well as in the 

 •constituent elements of which they are composed. A careful examination, how- 

 ever, will show that every seed contains a living germ or embryo, which is really 

 a plant in miniature, in or around which is stored up a supply of food for the 

 nutriment of the young plant till it shall have attained age and strength to secure 

 this from the soil and air. The materials thus stored up consist of starch, gluten, 

 albumen, oils, gums, and various other substances. The kernel of most seeds is 

 composed largely of starch and the albuminous compounds. It differs, however, 

 in different plants, being oleaginous in the poppy, castor bean and peanut; muci- 

 laginous in the flax, fleshy in the pgeony and barberry, corneous or horny in the 

 coffee, and having the appearance and consistence of ivory in the ivory-palm. 

 The seeds of the cereal grains and of grasses are chiefly composed of starch. 

 The wisdom and goodness of the Creator are strikingly shown in the selection of 

 this material to compose the principal part of the seeds of that class of plants upon 

 which not only the well being but the very existence of man and the higher ani- 

 mals depend. Starch is not only a very important article of food but it is a sub- 

 stance not readily affected by cold or moisture, hence seeds composed of this 

 material will endure great exposure without injury to their vitality. Germination, 

 or the awakening of the plant germ to active life is affected, and, to a considera- 

 ble extent, controlled by several external influences. The plant food stored up 

 in the seed cannot be appropriated to the use of the germ until reduced to a liquid 

 condition. Or in other words the plant cannot digest solid food. But it must 

 not only be dissolved but it must be conveyed from those parts of the seed where 

 it is stored to the germ before it can be used by that or for its benefit. For these 

 purposes water is essential to the germinating seed. But there is a limit to the 

 amount of water that is beneficial to the seed at this time. 



Aquatic plants grow very well in the water, and many seeds of land plants 

 will germinate when immersed in water, but they will not make a healthy growth 

 I in the presence of so much water as to exclude the air. For most seeds a moist 

 but not wet soil is most conducive to a healthful germination and vigorous 

 growth. 



The presence of atmospheric air is also essential to the proper germination 

 of seed. This will be better understood when we consider the changes that take 

 place in the seed during the process of germination. A growing plant in the 

 presence of air and sunlight absorbs, through its leaves, carbonic acid from the 

 air; this is decomposed in the plant and the oxygen is expelled while the carbon 

 is employed in building up the plant structure. This process can take place only 

 in the presence of sunlight. The reverse of this takes place in the process of ger- 

 mination, which is generally most readily performed in the dark. During this pro- 

 cess the seed absorbs oxygen which, combining with a portion of the carbon of 

 the seed, forms carbonic acid or carbonic anhydride, as the chemists now call it, 

 which is given off to the surrounding air, thus reducing the substance of the 

 seed. The total loss in this process, according to Boussingault, was, in an exper- 

 iment of his as follows : 



