OXYGEN.—One of the chemical elements.
PATHOLOGY.—The branch of medicine which deals with the altered structure and activity of diseased organs.
PEPSIN.—A ferment found in the digestive juice secreted by the stomach.
PELVIC FLOOR.—The muscles, ligaments, and other tissues which form the bottom of the basin inclosed between the hips.
PELVIS.—The bony ring formed chiefly by the hip bones. Posteriorly the ring is completed by the sacrum.
PERINEUM.—The region extending backward from the outlet of the vagina to the rectum; it is the most essential part of the pelvic floor.
PHYSIOLOGY.—Scientific knowledge of the manner in which the various parts of the body perform their duties.
PIGMENT.—Any coloring matter.
PLACENTA.—The organ through which the communication between the mother and the offspring is established. One of its surfaces is attached to the wall of the uterus; at about the middle point of the other surface the umbilical cord takes its origin.
PRENATAL.—Pertaining to the period before birth.