Glossary 639 



Saturated solution: A liquid which has dissolved as much of a soluble 

 substance as it can hold. 



Scald: An injury caused by contact with steam or boiling water. 



Scanning disk: A circular piece of metal pierced by a spiral series of 

 holes ; an essential part of a television sending apparatus. 



Scavenger: Any animal which devours refuse. 



Schaefer method (sha'fer) : An efficient method of artificial respiration 

 to overcome suffocation; consists of the alternate application and re- 

 lease of pressure from behind on the lower ribs. 



Schick test (shlk) : A test to show whether one is susceptible to diph- 

 theria. 



Science : Classified knowledge of the facts about nature. 



Scientific method: The definite experimental plan by which scientists 

 work, involving observation, comparison, and conclusion. 



Sclerotic coat (skle-rot'ik) : The opaque outer coat which covers all of 

 the eye except the iris and the pupil. 



Screw: A form of the inclined plane, consisting of a continuous groove 

 or ridge wound at an angle about a cylinder. One of the basic ma- 

 chines. 



Screw propeller: Two or more metal blades, resembling the blades of 

 an electric fan, set at an angle on a shaft, and located at the stern of 

 a ship below the water line. The pressure of the revolving blades 

 against the water moves the ship. 



Searchlight: A powerful lamp which throws a long, narrow beam of 

 light a great distance. 



Secrete (se-kret') : To produce and give off. The liver secretes bile. 



Sedentary (sed'<?n-ta-ri) : Seated; obtaining little exercise, as the seden- 

 tary life of an accountant. 



Sediment: Solid matter which settles to the bottom of a liquid. 



Sedimentary rocks (sed-i-men'td-ri) : Rocks formed by material de- 

 posited in layers. Sandstone and shale are examples. 



Seedling : A sprouting seed. 



Semicircular canal (sem-i-sur'ku-lar) : The curved tubular part of the 

 inner ear, filled with liquid. The influence of the semicircular canal 

 on hearing is not known. It is the organ which enables us to keep 

 our balance. 



Sensation: The feeling resulting from the stimulation of a sense organ; 

 for example, the effect of sound on the ear. 



Septic tank: A tank for making sewage harmless by the action of bac- 

 teria. 



Serum (se'rwrn) : The watery part of certain animal fluids, such as 

 blood or milk, separated from them by coagulation, or clotting. 



Sewage (su'aj) : Wastes from the household. 



Sextant: An instrument used in navigation to determine latitude. 



Shadow: A dark space caused by an opaque object cutting off light. 



Shock: A type of illness characterized by dizziness, shortness of breath, 

 nausea, and sometimes unconsciousness. Often the result of a sudden 

 injury. 



Sidereal system (si-de're-al) : The starry system. 



Sight: Ability to see; vision. 



Silica (sil'i-kd) : A mineral having binding qualities; common in sand- 

 stones and sands ; used in making glass and pottery. 



Siphon (si'fon) : A device for transferring liquid over an elevation to 

 a lower level. 



Skeleton: The bony framework of the body. 



