292 Elementary Principles of Agriculture ' 



their own food products; i. e., incapable of carbon assimilation. 

 Digestion. The process of converting the insoluble substances of 



foods into soluble materials, preparatory to absorption into 



the blood. 

 Drainage. Removing surplus water from the soil, either by ditches. 



terraces or tiles. 

 Ecology. The science which treats of the inter-relationships between 



animals and plants, and their environments. The study of the 



modes and conditions of life of plants and animals, a very 



important phase of agricultural science. 

 Element. A substance that has only one form of matter. An original 



form of matter. 

 Emulsion. A more or less permanent and complete mixture of oils 



or fats and water. Fresh milk is an excellent illustration. 

 Endosperm. Reserve food in seeds stored outside of the embryo. 

 Energy. Power; force. Every movement of, or change of body, 



expends energy. The energy of sunlight may be expressed in 



sunlight heat, or other form of energy. 

 Ensilage. Green foods preserved in a silo. 

 Entomology. Science of insects. 



Erosion. Wearing away. Denudings, as of rocks or soils. 

 Ether Extract. A term used in feed analyses to describe the substances 



removed by ether usually oils. 

 Evolution. The doctrine that present forms of plants and animals 



are descended from previous forms. A theory of the origin of 



forms of living organisms. 



Farming. The practice of raising crops and animals. 

 Farmstead. A farm home or establishment. 

 Fecundation. The union of male and female cells. 

 Fermentation. A chemical change produced by bacteria, yeast, 



etc. Example, souring of milk. The decay of any organic 



substance is due to a form of fermentation. 

 Fertilization. Used in the same sense as fecundation. 

 Fertilizer. A substance added to the soil to improve its productive- 

 ness, as compost. Some fertilizers are known as amendments, 



which see. 

 Fetlock. The long-haired cushion on the back side of a horse's leg, 



just above the hoof. 

 Fiber. Any fine thread-like substance, as the wood fibers of stems, 



cotton fiber, etc. 



