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GLOSSARY OF IMPORTANT TERMS 



Dorsal (dor'sal) : of or pertaining to 



the back or top side. 

 Ductless glands : glands which have 



no communication with an outer 



surface, and which manufacture 



hormones. 



Ecology (e kol'6 ji) : study of plants 

 and animals in relation to their 

 natural surroundings. 



Ectoderm (ek'to durm) : the outer 

 layer of cells in an embryo. 



Egg : the female gamete, the ovum. 



Embryo (em'bri o) : the early stage of 

 a developing plant or animal. 



Embryo sac : the structure within the 

 ovule which holds the egg cell. 



Emulsion (e mul'shun) : a mixture of 

 liquids which do not dissolve, the 

 particles of one floating as small 

 globules in the other. 



Enamel : hardest part of a tooth. 



Encyst (en slst') : to become inclosed 

 in an impermeable envelope or cyst. 



Endocrine glands (en'do krin) : duct- 

 less glands. 



Endoderm (en'do durm) : the inner 

 layer of cells in an embryo, giving 

 rise to the digestive tract, etc. 



Endoskeleton (en'do skeTe tun) : a 

 skeleton inside the body as opposed 

 to the outer or exoskeleton. 



Endosperm (en'do spurm) : food 

 stored in the seed outside the em- 

 bryo. 



Energy : work power ; ability to per- 

 form work. It may be latent or 

 kinetic. 



Environment (en vi'rwn ment) : the 

 surroundings of an organism. 



Enzyme (en'zim) : a substance which 

 brings about a chemical action, 

 assisting in digestion. 



Epidermis (ep'I dur'mis) : an outer 

 layer of cells ; the outside skin. 



Epiglottis (ep'I glot'is) : a covering 

 over the opening into the trachea. 



Erosion (e ro'zhun) : the wearing 

 away of rocks by water, wind, gla- 

 ciers, and other agents. 



Esophagus (e sofa g#s) : muscular 

 tube leading from the pharynx to 

 the stomach ; gullet. 



Essential organs : the stamens and 

 pistils, parts of a flower which have 



to do with the production of 



Eugenics (ti jen'iks) : the science 

 which deals with race improvement 

 through heredity. 



Eustachian tube (u sta'ki an) : the 

 canal connecting the tympanic cav- 

 ity with the pharynx, named for its 

 discoverer, Eustachio, an Italian 

 physician. 



Euthenics (u then'iks) : the science 

 which deals with race improvement 

 through betterment of the environ- 

 ment. 



Excretion (eks kre'smm) : elimination 

 of waste products from an organ- 

 ism. 



Exoskeleton (Sk'so skel'e tun) : an 

 outside skeleton. 



Expiration : process of forcing air out 

 of lungs. 



Fi, F 2 , etc. : abbreviations indicating 

 the successive generations follow- 

 ing crossing or hybridizing. 



Fatigue (fd teg') : the effect produced 

 by prolonged stimulation on the 

 cells of an organism. 



Fats : a class of nutrients composed of 

 much carbon and hydrogen with a 

 little oxygen. 



Fermentation (fur'men ta'shan) : the 

 chemical transformation of organic 

 substances through the agency of 

 enzymes or ferments, or through 

 the agency of bacteria. 



Fertilization (fur'ti li za'sMn) : the 

 union of an egg cell and a sperm cell. 



Fibrinogen (fi brm'6 jen) : a soluble 

 protein substance in the blood 

 plasma. 



Fibrovascular bundles : collections of 

 tubular cells, supported by woody 

 cells, which conduct fluids in plants. 



Fin : a fold of skin, with skeletal 

 supports, used for swimming. 



Fission (fish'wn) : division of a cell 

 into two cells of equal size. 



Flagellum (fld jeTwrn) : a threadlike 

 projection of certain cells, which is 

 used for locomotion. 



Focus of infection : a center of bac- 

 terial infection, often at the base of 

 a tooth, from which toxins reach 

 the blood. 



