CON-VUL´SION (L. _convel´lo_, to pull together). A more or less violent agitation of the limbs or body. COR´NE-A (L. _cor´nu_, a horn). The transparent, horn-like substance which covers the anterior fifth of the eyeball. COR´PUS-CLES, BLOOD (L. dim. of _cor´pus_, a body). The small biconcave disks which give to the blood its red color; the _white_ corpuscles are globular and larger. COS-MET´IC (Gr. [Greek: kosmeô], _kosmeo_, to adorn). Beautifying; applied to articles which are supposed to increase the beauty of the skin, etc. CRA´NI-AL (L. _cra´nium_, the skull). Pertaining to the skull. The nerves which arise from the brain are called cranial nerves. CRI´COID (Gr. [Greek: krikos], _kri´kos_, a ring). A cartilage of the larynx, resembling a seal-ring in shape. CRYS´TAL-LINE LENS (L. _crystal´lum_, a crystal). One of the so-called humors of the eye; a double convex body situated in the front part of the eyeball. CU´TI-CLE (L. dim. of _cu´tis_, the skin). The scarf-skin; also called the _epider´mis_. CU´TIS (Gr. [Greek: skutos], _skutos_, a skin or hide). The true skin, lying beneath the cuticle; also called the _der´ma_. DE-CUS-SA´TION (L. _decus´sis_, the Roman numeral ten, X). A reciprocal crossing of fibres from side to side. DI´A-PHRAGM (Gr. [Greek: diaphrassô], _diaphrasso_, to divide by a partition). A large, thin muscle which separates the cavity of the chest from the abdomen; a muscle of respiration. DIF-FUS´ION OF GASES. The power of gases to become intimately mingled, without reference to the force of gravity. DUCT (L. _du´co_, to lead). A narrow tube; the _thoracic duct_ is the main trunk of the absorbent vessels. DU-O-DE´NUM (L. _duode´ni_, twelve). The first division of the small intestines, about twelve fingers-breadth long. {256} DU´RA MA´TER (L.). Literally, the hard mother; the tough membrane which envelops the brain. DYS-PEP´SI-A (Gr. [Greek: dus], _dus_, difficult, and [Greek: peptô], _pep´to_, to digest). Difficult or painful digestion; a disordered condition of the stomach. E-MUL´SION (L. _emul´geo_, to milk). Oil in a finely divided state suspended in water. EN-AM´EL (Fr. _email_). The dense material which covers the crown of the tooth. EN´ER-GY, Specific, of a Nerve. When a nerve of special sense is excited, whatever be the cause, the sensation experienced is that peculiar to the nerve; this is said to be the law of the specific energy of the nerves. EP-I-GLOT´TIS (Gr. [Greek: epi], _epi_, upon, and [Greek: glôttis], _glottis_, the entrance to the windpipe). A leaf-shaped piece of cartilage which covers the top of the larynx during the act of swallowing. EX-CRE´TION (L. _excer´no_, to separate). The separation from the blood of the waste particles of the body; also the materials excreted. EX-PI-RA´TION (L. _expi´ro_, to breathe out). The act of forcing air out of the lungs.