284 WHAT 18 LIFE 



bacteria are able to survive extreme cold. Paul 

 Becquerel kept bacteria for many hours at a tempera- 

 ture of 253°C. below zero, and yet they retained their 

 vitality. Some bacteria or the poisons generated by 

 them, according to E. O. Jordan, may survive boil- 

 ing. Morphologically, bacteria are rod-shaped (ba- 

 cilli); or in shape like twisted rods (spirella); or 

 spherical (cocci). Methods that make possible 

 the examination of the structure of living bacteria 

 have been available since, some years ago, J. E. 

 Barnard, the English optical physicist, discovered 

 methods whereby to secure a useful magnification 

 of 3,000 diameters, that is, the magnifying of an 

 object twelve and one-half million times, showing 

 detail. (Ultramicroscopes of even greater power 

 have since been perfected; one by F. F. Lucas, 

 with a magnification to 9,000 diameters, and one 

 yet more powerful by W. G. Guthrie.) 



Bathybic Life-forms. Life-forms that inhabit the 

 deep sea. 



Brownian Movement. The constant rapid and os- 

 cillatory motion of fine particles of a substance sus- 

 pended in a liquid. Named for the botanist Dr. 

 Robert Brown, who first treated of the phenomenon 

 in 1827. Brownian movement is also exhibited by 

 the molecules of a gas. See Kinetic Theory of Gases. 



c. Symbol for the velocity of light. See Velocity 

 of Light. 



Cancer. "Any malignant growth." 



Catalysis. The phenomenon in which many reac- 

 tions that otherwise proceed very slowly have their 

 velocities increased in the presence of certain sub- 

 stances, which latter in most cases themselves re- 

 main chemically unchanged. In some cases reactions 

 are retarded. 



Catalyser (Catalyst). A chemical substance which 



