666 



SUBJECT INDEX 



Time factor in research, 22-25 

 Tiselius electrophoresis apparatus, 289- 



95 

 Tracers. See Stable isotopes and Radio- 

 isotopes. 

 Tracks, ionizing particles, 506-7, 517 

 Tradescantia, pollen tubes, 507 



U 



Ultracentrifugal method, accuracy and 

 limitations, 96-97 



applications, 97 



experimental requirements, 86-94 



frictional ratio, 94-95 



homogeneity of boundary, 94-96 



interpretation of results, 94-98 



light absorption method, 77-79, 93 



sampling techniques, 100 



significance, 71-72 



theory, 83-86 

 Ultracentrifuges, optical, 72-77 



optical, air friction type, 77 

 Svedberg, 75-77 

 vacuum type, 72-75 



preparative, 98-99 



resolving power, 90-91 



selection of, 90-94 

 Ultrasonic vibrations, 301-42 



absorption and scattering, 311-2, 

 333-5 



biological applications, 328-39 



biological effects, 328-35 



cavitation and degassing, 312-4, 

 329-32 



chemical effects, 335-6 



coagulation effects, 337-8 



concepts and definitions, 301-14 



emulsification, 336-7 



intensity, 307-8, 326-8 



lethal effects, 328-33 



measurements, 326-8 



natural sources, 338-9 



pressure, 304, 308 



production, 314-26 



reflection and transmission, 305-7, 

 309-10 



thermal effects, 333-5 

 Ultraviolet microscopy, 352-4 



Ultraviolet radiation, 419, 422 



sources, 433-4 

 Undercooling, 56-57 



Vacuum-tube electrometer, 249-54 

 van't Hoff, law, 46, 48-52 

 Variation, biological, 204 

 Velocity, sound, 302-3 

 Vertical illuminators, 356-8 

 Victoreen ionization chamber, 457, 546 

 Virus, preservation, 216, 226-8 



X irradiation, 473-5 

 Virus problem (electron microscope), 



413-5 

 Viscometer, Hess, 110-11 

 Viscosity, blood, 110, 125, 127, 128 



coefficient, 274-5 



concept, 109-10 



correction (ultracentrifugation), 87 



definition, 109-10 



importance in biology, 107-9, 127-9 



protoplasm, HI ff., 126-8 

 Viscosity measurements, 107-30 



Brownian movement method, 121-4 



centrifuge method, 112, 116-21 



future possibilities, 127-9 



gravity method, 112-6 



magnetic method, 112 



results, 125-7 



theoretical considerations, 112-4 

 Vision, pho topic, 419, 431-3, 443 



scotopic, 431-3, 443 



spectral, 431-3, 443 

 Voltage measurements. See Potential 

 measurements. 



W 



Water, decomposition by radiation, 

 516-18 



heavy, 532-3, 574, 594 

 Wheatstone bridge circuit, 157-9 

 Work, concentration, 42 



osmotic, 43 



X irradiation, 451-90 



bacterial mutations, 480-2 



