CARBOHYDRATE.—Any one of a group of chemical substances of which starch and sugar are the most familiar members.
CARBONIC ACID GAS.—An animal waste product eliminated in the breath. In daylight plants absorb it energetically from the atmosphere through their leaves, and decompose it, assimilating the carbon, and returning the oxygen to the air.
CARTILAGE.—A firm, elastic tissue; gristle. From this material many of the bones develop.
CATHETERIZE.—To empty the bladder by means of a tube-like instrument which is introduced into the passage through which the urine normally leaves the bladder.
CELL.—One of the microscopical structural units which make up our bodies.
CELL-DIVISION.—The process by which a single cell becomes two cells.
CEREBRUM.—The portion of the brain which is the seat of mental activity.
CHORIONIC MEMBRANE.—The outermost of the two membranes which surround the embryo.
CHROMATIN.—A substance within the nucleus of a cell which has a special affinity for certain staining agents.
CHROMOSOMES.—One of the pieces into which the chromatin is broken during the act of cell-division.