Bunion. An enlargement and inflammation of the first joint of the great toe. Bursa. A pouch; a membranous sac interposed between parts which are subject to movement, one on the other, to allow them to glide smoothly. Callus (Lat. _calleo_, to be thick-skinned). Any excessive hardness of the skin caused by friction or pressure. Canal (Lat. _canalis_, a canal). A tube or passage. Capillary (Lat. _capillus_, hair). The smallest blood-vessels, so called because they are so minute. Capsule (Lat. _capsula_, a little chest). A membranous bag enclosing a part. Carbon Dioxid, often called _carbonic acid_. The gas which is present in the air breathed out from the lungs; a waste product of the animal kingdom and a food of the vegetable kingdom. Cardiac (Gr. καρδία, the heart). The cardiac orifice of the stomach is the upper one, and is near the heart; hence its name. Carnivorous (Lat. _caro_, flesh, and _voro_, to devour). Subsisting upon flesh. Carron Oil. A mixture of equal parts of linseed oil and lime-water, so called because first used at the Carron Iron Works in Scotland. Cartilage. A tough but flexible material forming a part of the joints, air passages, nostrils, ear; gristle, etc. Caruncle (Lat. _caro_, flesh). The small, red, conical-shaped body at the inner angle of the eye, consisting of a cluster of follicles. Casein (Lat. _caseus_, cheese). The albuminoid substance of milk; it forms the basis of cheese. Catarrh. An inflammation of a mucous membrane, usually attended with an increased secretion of mucus. The word is often limited to _nasal_ catarrh. Cauda Equina (Lat., horse’s tail). The collection of large nerves descending from the lower end of the spinal cord. Cell (Lat. _cella_, a storeroom). The name of the tiny miscroscopic elements, which, with slender threads or fibers, make up most of the body; they were once believed to be little hollow chambers; hence the name. Cement. The substance which forms the outer part of the fang of a tooth. Cerebellum (dim. for _cerebrum_, the brain). The little brain, situated beneath the posterior third of the cerebrum. Cerebrum. The brain proper, occupying the upper portion of the skull. Ceruminous (Lat. _cerumen_, ear wax). A term applied to the glands secreting cerumen, or _ear wax_. Chloral. A powerful drug and narcotic poison used to produce sleep. Chloroform. A narcotic poison generally used by inhalation; of extensive use in surgical operations. It produces anæsthesia. Chondrin (Gr. χονδρός, cartilage). A kind of gelatine obtained by boiling _cartilage_. Chordæ Tendineæ. Tendinous cords. Choroid (Gr. χορίον, skin, and εἶδος, form). The middle coat of the eyeball. Chyle (Gr. χυλός, juice). The milk-like fluid formed by the digestion of fatty articles of food in the intestines. Chyme (Gr. χυμός, juice). The pulpy liquid formed by digestion in the stomach.