44O GLOSSARY 



Diffusion (Lat. diffusio), the act of passing through membranes appar- 

 ently impervious. Thus, peptone passes by diffusion through the sides 

 of the blood tubes in the walls of the intestine, and reaches the blood. 



Di-ges'tion (Lat. dis, apart, an&gerere, to carry or wear), changing food 

 into such forms that it can pass through the walls of the blood 

 tubes and become a part of the blood. 



Diph-the'ri-a (Gr. diphthera, leather), an infectious disease in which 

 there is a skin-like membrane covering the affected part, usually the 

 throat. 



Dis-lo-ca'tion (Lat. dis, apart, and locare, to locate), the separation of 

 two bones whose union forms a joint. 



Dis-til-la'tion (Lat. de, from, and stillare, to drop), the process of sepa- 

 rating a substance which easily becomes a vapor from one which 

 forms a vapor less easily. Heat is applied to the substance, and 

 the vapor is cooled or condensed to a liquid in a coil of tube from 

 which it runs in drops, and hence the name. As far back as the 

 year 1200 the process was used by the Arabs in their endeavors to 

 find an essential spiritual principle which would sustain life and 

 restore youth. 



Drop'sy, a uniform swelling of a part without pain or redness. It is 

 an accumulation of lymph due to a disturbance in the circulation of 

 the blood. 



Duct (Lat. ducere, to lead), any tube which conducts a secretion away 

 from a gland. 



Du-o-de'num (Lat. duodeni, twelve), the beginning of the small intes- 

 tine for the length of about twelve finger breadths. 



Du'ra ma'ter (Lat. dura, harsh, and mater, mother), the periosteum 

 lining the skull. It is very thick and sends prolongations into the 

 main fissures of the brain to hold the brain in place. 



Dys-pep'si-a (Gr. dus, ill, and peptein, to cook or digest), imperfect 

 digestion of the food. 



E-mul'sion (Lat. e, out, and mulgere, to milk), a milky-looking liquid 



consisting of microscopic drops of oil floating in a liquid. 

 En-am' el, the hard calcified tissue which covers the exposed parts of 



the teeth. 

 En'er-gy (Gr. en, in, and ergon, work), any force which can be made 



to do work. The energy of the body can be traced to oxidation 



within the cells. 



