Glossary 637 



Pulmotor: A device for pumping air into and out of the lungs; used 



in artificial respiration. 

 Pulse: Throbbing of the arteries caused by the wave-like motion of 



the blood within them. 

 Punctured wound: A deep wound with a small opening, such as from 



the stab of a sharp instrument or from a bullet. 

 Pupa (pu'pd) : The young of certain insects in the sleeping stage of 



their development that precedes the adult stage. The cocoon holds the 



pupa of the moth. 

 Pupil: The adjustable opening of the eye through which light passes 



to reach the lens. 



Putrefaction (pu-tre-fak'shwn) : Offensive state of decay. 

 Pylorus (pi-16'rws) : The opening from the stomach into the small 



intestine. 

 Pyorrhea (pl-d-re'd) : A disease of the gums which causes loss of teeth. 



Quarantine (kwor'an-ten) : Separation from other people of those who 

 have an infectious disease or who have been exposed to it. 



Radiant energy: Energy received from the sun, including both light 



and heat energy. 

 Radiation: The flow of heat from a body in straight lines in all 



directions. 

 Radiator: A number of connected loops of pipe in a steam or hot water 



plant, which give off heat by radiation. 

 Radio: A method of wireless communication by which sound is sent 



and received in the form of waves in the ether. 

 Radio beacon: An automatic radio sending set which broadcasts signals 



to guide ships and airplanes on their courses. 

 Radiometer (ra-di-om'e-ter) : An instrument for detecting the presence 



of and measuring the intensity of small amounts of heat energy. 

 Radium: A rare metallic element which spontaneously gives off rays 



containing particles of the material itself ; found in minute quantities. 

 Rain: Drops of water formed by the condensation of water vapor in 



the air. 

 Rainbow: A natural spectrum stretching in an arc across the sky; 



formed by the breaking up of sunlight as it passes through raindrops. 

 Rain gauge: A device for measuring the quantity of rainfall. 

 Ray: A single line of light too small to be seen. 

 Rayon: Artificial silk made from wood pulp. 

 Receiver: The earpiece of a telephone which receives messages. 

 Red corpuscles (kor'pus-'lz) : Small red cells in the blood which convey 



oxygen from the lungs to the cells of the body. 

 Reflection: The turning back of light or sound from an object. 

 Reflex action: Action directed by the spinal cord without the aid of 



the brain. Aids as a protection against injury and relieves the brain 



of work. 



Reforestation: The replacing of used forests with new growth. 

 Refraction: The bending of a beam of light when it passes at an angle 



from one medium into another of different density. 



