GLOSSARY 



689 



Ere-ment (L. elementum, of obscure ori- 

 gin). A simple substance which can- 

 not be decomposed by ordinary chemi- 

 cal means and consisting of one kind 

 of atom. 



Em'bry-o (Gr. emhnjon, embryo). The or- 

 ganism in an early stage of develop- 

 ment. 



Em'bry-or'o-gy (Gr. emhnjon, embryo; lo- 

 gos, discourse). The science of the 

 development of the organism. 



E-mursi-fi-ca"tion (L. e, out; mulgere, to 

 milk ) . The process of dividing fat into 

 particles of very small size. 



En-cyst' (Gr. en, in; kijstis, bladder). To 

 become enclosed in a cyst. 



En'do-crine (Gr. enclon, within; krinein, to 

 separate). Pertaining to a ductless 

 gland. 



En'do-derm (Gr. endon, within; derma, 

 skin ) . The innermost germ layer of the 

 gastrula which gives rise to the lining 

 of the digestive tract and its deriva- 

 tives. 



En'do-mix"is (Gr. endon, within; mixis, a 

 mingling). The non-sexual reorganiza- 

 tion of nuclear material in some Pro- 

 tozoa. 



En'do-par"a-site (Gr. endon, within; para, 

 beside; sitos, food). A parasite living 

 within the body of its host. 



En'do-plasm (Gr. endon, within; plasma, 

 something molded). Inner cytoplasm 

 surrounded by ectoplasm. 



En'do-sarc (Gr. endon, within; sarx, flesh). 

 Inner mass of protoplasm in a proto- 

 zoan. 



En'do-sker'e-ton (Gr. endon, within; skele- 

 tos, hard). Internal bony and cartilag- 

 inous structvire of animals. 



En'do-the"li-um (Gr. endon, within; thele, 

 nipple). Epithelial lining of the cir- 

 culatory organs. 



En'er-gy (Gr. energein, to be active). The 

 capacity to do work. 



En-ter-o-ki'nase (Gr. enteron, gut; kinein, 

 to move). Intestinal enzyme which ac- 

 tivates pancreatic trypsinogen. 



En'ter-on (Gr. enteron, gut). That part of 

 the digestive tract derived from endo- 

 derm. 



En'to-derm. See Endoderm. 



En'to-mor'o-gy (Gr. entomon, insect; logos, 

 discourse). The study of insects. 



En-vi'ron-ment (Fr. environ, about, there- 

 abouts ) . External or internal surround- 

 ings. 



En'zyme (Gr. en, in; zijme, leaven). Or- 

 ganic catalyst. 



Ep-i-der'mis (Gr. epi, upon; derma, skin). 

 The outermost laver of the skin. 



Ep'i-gen"e-sis (Gr. epi, upon; gignesthai, to 

 be born). The concept that develop- 

 ment begins with an undifferentiated 

 cell. 



Ep-iph'y-sis (Gr. epi, upon; phyein, to 

 grow). The tip of a bone separated in 

 early development by cartilage but 

 later becoming a part of the bone. 



Ep'i-the"li-um (Gr. epi, upon; thele, nip- 

 ple). A sheet of cells covering either 

 external or internal parts of body sur- 

 faces. 



E'qua-to"ri-al plate (L. aequator, one who 

 equalizes ) . The plate-like arrangement 

 of chromosomes formed at the equator 

 during cell division. 



E-rep'sin (L. eripere, to set free). A mix- 

 ture of peptone and proteose-splittino; 

 enzymes produced by the intestinal 

 mucosa. 



E-soph'a-gus (Gr. oisophagos, gullet). The 

 tube extending from the p)harynx to the 

 stomach. 



Es'ti-va"tion (L. aestivus, pertaining to 

 summer). Inactivity brought about by 

 extreme dryness and heat. 



Es'tro-gen (L. aesttis, fire, glow). A hor- 

 mone produced by the ovarian follicle 

 which, together with one of the pitui- 

 tary hormones, influences estrus. 



Es'trus (L. aestus, fire, glow). The mating 

 period in female mammals marked by 

 intensified sexual urge. 



Eu-gen'ics ( Gr. eii, well; genos, birth ) . The 

 science of applying genetic knowledge 



