SYS´TO-LE (Gr. [Greek: sustellô], _sustello_, to contract). The contraction of the heart, by which the blood is expelled from that organ. TAC´TILE (L. _tac´tus_, touch). Relating to the sense of touch. TEM´PO-RAL (L. _tem´pus_, time, and _tem´pora_, the temples). Pertaining to the temples; the name of an artery: so called, because the hair begins to turn white with age in that portion of the scalp. TEN´DON (L. _ten´do_, to stretch). The white, fibrous cord or band by which a muscle is attached to a bone; a sinew. TET´A-NUS (Gr. [Greek: teinô], _teino_, to stretch). A disease marked by persistent contractions of all or some of the voluntary muscles; those of the jaw are sometimes solely affected: the disorder is then termed locked-jaw. THO´RAX (Gr. [Greek: thôrax], _thorax_, a breastplate). The upper cavity of the trunk of the body, containing the lungs, heart, etc.; the chest. THY´ROID (Gr. [Greek: thureos], _thureos_, a shield). The largest of the cartilages of the larynx; its angular projection in the front of the neck is called "Adam's apple." TRA´CHE-A (Gr. [Greek: trachus], _trachus_, rough). The windpipe, or the largest of the air-passages; composed in part of cartilaginous rings, which render its surface rough and uneven. TRANS-FU´SION (L. _transfun´do_, to pour from one vessel to another). {263} The operation of injecting blood taken from one person into the veins of another; other fluids than blood are sometimes used. TRICH-I´NA SPI-RA´LIS. (L.) A minute species of parasite or worm, which infests the flesh of the hog, and which may be introduced into the human system by eating pork not thoroughly cooked. TYM´PA-NUM (Gr. [Greek: tumpanon], _tumpanon_, a drum). The cavity of the middle ear, resembling a drum in being closed by two membranes, and in having communication with the atmosphere. U´VU-LA (L. _uva_, a grape). The small pendulous body attached to the back part of the palate. VAS´CU-LAR (L. _vas´culum_, a little vessel). Pertaining to, or containing blood-vessels. VE´NOUS (L. _ve´na_, a vein). Pertaining to, or contained within a vein. VEN-TI-LA´TION. The introduction of fresh air into a room or building, in such a manner as to keep the air within it in a pure condition. VEN-TRIL´O-QUISM (L. _ven´ter_, the belly, and _lo´quor_, to speak). A modification of natural speech by which the voice is made to appear to come from a distance. The ancients supposed that the voice was formed in the belly; hence the name. VEN´TRI-CLES of the heart. The two largest cavities of the heart, situated at its apex or point. VER´TE-BRAL COLUMN (L. _ver´tebra_, a joint). The back-bone, consisting of twenty-four separate bones, called vertebræ, firmly jointed together; also called the spinal column and spine. VES´TI-BULE. A portion of the internal ear, communicating with the semicircular canals and the cochlea; so called from its fancied resemblance to the vestibule or porch of a house.