GERMINAL CELLS.—The structural units from which a new individual takes origin. The cell contributed by the mother is called an egg- cell or ovum; that contributed by the father, a spermatozoon.

GESTATION.—Same as pregnancy.

GLAND.—An organ which separates certain substances from the blood, and pours out a material, usually fluid, peculiar to itself.

HYGIENE.—That department of medical knowledge which relates to the preservation of health; sanitary science.

INANITION.—The condition which results from insufficient nourishment.

INFECTION.—A disease due to bacteria.

INTESTINE.—The bowels; the long membranous tube extending from the stomach to the rectum.

INVOLUTION.—The process by which the uterus returns after child- birth to its former size and position.

LACTATION.—The secretion of milk.

LIGAMENT.—A band of tissue serving to bind one part of the body to another.