Pronation (Lat. pronus, inclined forwards). The turning of the hand with the palm downwards.
Pronator. The group of muscles which turn the hand palm downwards.
Proteids (Gr. πρῶτος, first, and εἶδος, form). A general term for the albuminoid constitutents of the body.
Protoplasm (Gr. πρῶτος, first, and πλάσσω, to form). A first-formed organized substance; primitive organic cell matter.
Pterygoid (Gr. πτέρων, a wing, and εἶδος, form, resemblance). Wing-like.
Ptomaine (Gr. πτῶμα, a dead body). One of a class of animal bases or alkaloids formed in the putrefaction of various kinds of albuminous matter.
Ptyalin (Gr. σίαλον, saliva). A ferment principle in saliva, having power to convert starch into sugar.
Pulse (Lat. pello, pulsum, to beat). The throbbing of an artery against the finger, occasioned by the contraction of the heart. Commonly felt at the wrist.
Pupil (Lat. pupilla). The central, round opening in the iris, through which light passes into the interior of the eye.
Pylorus (Gr. πυλουρός, a gatekeeper). The lower opening of the stomach, at the beginning of the small intestine.