Contents xlii 



25. Information Theory and Biology 460 



/. Languages, 460 ; 2. Information Theory — General Discus- 

 sion, 46 1 ; 3. Information and Sensory Perception, 467 ; 4. In- 

 formation Theory and Protein Structure, 47 1 ; 5. The Coding of 

 Genetic Information, 474; 6. Summary, 475 



F. Specialized Instrumentation 



26. Absorption Spectrophotometry 481 



/. Role of Absorption Spectrophotometry in Biology, 48 1 ; 2. Units 

 and Symbols of Absorption, 484; 3. Spectrophotometers, 488; 

 4. Flow Systems, 495 ; 5. Split-Beam and Dual-Beam Spectro- 

 photometers, 496 



27. Quantum Mechanical Basis of Molecular Spectra 501 



/. Introduction, 50 1 ; 2. An Elementary Approach to Quantum 

 Mechanics, 502; 3. Molecular Spectra — Rotational and Vibra- 

 tional Bands, 509 ; 4. Electronic Levels of Atoms and Molecules, 



516 



28. Magnetic Measurements 525 



1. Magnetic Effects in Biology, 525 ; 2. Paramagnetism and 

 Diamagnetism, 526 ; 3. Static Measurement Techniques, 528 ; 

 4. Resonance Measurements, 531; 5. Limitations and Applications 

 of Magnetic Measurements, 534 



29. Microscopy 537 



/. Types of Microscopes, 537; 2. The Bright-Field Light Micro- 

 scope, 538 ; 3. The Dark-Field Microscope, 542 ; 4. Phase- 

 Contrast Microscopy, 544 ; 5. Interference-Contrast Microscopy, 545 ; 

 6. The Polarizing Microscope, 548 ; 7. Ultraviolet and X-ray Mi- 

 croscopes, 550 ; 8. The Electron Microscope, 5o 1 



30. Tracer Techniques 557 



1. Introduction, 557 ; 2. Radioactive Tracers, 558 ; 3. C 14 , 

 563; 4. 7 131 , 565; 5. P 32 , 566; 6. Stable Isotopes, 567; 

 7. jV 15 , 568; 8. Summary, 570 



