CHAPTER XI 



WHEN TO USE SPECIAL MICROSCOPES 



Oscar W. Richards, American Optical Co. 



A . Properties of Materials Essential for Microscopy 344 



1. Image Formation — Possibilities and Limitations 344 



2 . Nature of Specimen Determines Choice of Microscope and 



Method 348 



B . Colored Specimens — Brightfield Microscopy 349 



C. Specimens That Absorb Nonvisible Radiation 351 



1 . Infrared Microscopy 351 



2 . Ultraviolet Microscopy 352 



D . Opaque Specimens 354 



1 . Direct Illumination 354 



2 . The Stereoscopic, Biobjective Microscope 355 



3 . Vertical Illumination ^ 356 



4 . Epi-illumination 358 



E . Small and Ultramicroscopic Specimens That Scatter Light . . . 358 



1 . Darkfield Microscopy 358 



2 . Ultramicroscopy 360 



3 . Optical Staining 360 



F. Specimens That Polarize or Change Polarized Light 361 



G . Fluorescent and Phosphorescent Specimens 363 



H. Surface Irregularities and Optical Nonuniformity of Speci- 

 mens — Interference Microscopy . 365 



I. Transparent and Slightly Absorbing Specimens — Phase Mi- 

 croscopy 366 



J . Specimens That Require Manipulation 369 



1 . Microdissection, Microincineration, and Radioautographs 369 



2. Stereoscopic and Inverted Microscopes 370 



K. Inaccessible Specimens and Specialized Microscopes 371 



L . Useful Accessory Equipment and Recording Methods 372 



1 . Illumination and Its Importance 372 



2 . Accessory and Special Equipment 373 



3 . Counting and Measuring 375 



4 . Drawing, Projection, and Records 376 



References 377 



343 



