496 GLOSSARY 



Pyrex'ia. [From the Gr. pyresso, (fut.) pyrexo, to " have a fever."] Ele- 

 vation of temperature ; fever. 



Quad'rate. [From the Lat. quadratus, '' make four-cornered, or square."] 



Siiuare. (A small lobe of the liver.) 

 Quad'riceps. [From the Lat. quatuor, " four," and caput, the " head."] 



A term applied to the extensor muscle of the leg, having four heads, 



or parts. 



Rac'emose. [From the Lat. racemus, a "bunch of grapes."] Temi appUed 

 to compound, saccular glands, from their supposed resemblance to 

 a bunch of grapes. 



Radia'tion. [From the Lat. radiare, to " furnish with spokes or wheels."] 

 The (hffusion of rays of hght. 



Ra'dius. [Lat. a " rod," the " spoke of a wheel."] The outer bone of the 

 forearm, so called from its shape. 



Rile. [From the Fr. raler, to " rattle in the throat."] A rattling, bub- 

 bhng sound attending the circulation of air in the lungs. Different 

 from the murmur produced in health. 



Rec'tus. pi. Rec'ti. [Lat.] Straight. 



Reflec'tion. [From the Lat. re + flectere, to "bend or turn."] The 

 return of rays, beams, sound, or the like from a surface. Reflection 

 of light is of two kinds, regular and diffused. When a beam of light 

 enters a darkened room through a small opening and strikes a mirror, 

 a reflected beam will be seen travelling along some definite path. 

 This is called regular reflection. Should the light, however, fall on 

 a piece of white paper, it would be reflected and scattered in all direc- 

 tions. Tliis is called diffused reflection and is caused by the inequali- 

 ties of the reflecting surface. All rough surfaces, as well as dust and 

 moisture in the atmosphere, serve to diffuse light. If this were not 

 the case, it would be dark everj'where except in the direct path of 

 light from some luminous body. 



Refrac'tion. [From the Lat. re -\- frangere, to "break."] The bending 

 or deviation in tlic course of rays of hght in passing obliquely from 

 one transparent medium into another of different densitj'. Light 

 waves travel with different velocities in mediums of different dei>- 

 sities, the more dense the medium, the less the velocity. For 

 instance, light will travel less rapidly in water than in air. For 

 this reason where a ray of light in air strikes a body of wat«r 

 obliquely, it will be bent out of a straight hne, as shown in the 



