chapter  2
10 Pages

Optical Contrasting Techniques

Staining a specimen is not always convenient, or even possible, especially in the case of living cells. It is clear that all the structures inside the living cell differ in some way from their surroundings — why, then, are we often unable to see them in the microscope? The answer is that they differ from their surroundings in refractive index, but not in the amount they absorb light.