Stereology: methods for quantitative light and electron microscopy

There are available to the biologist sophisticated methods for the quantitative determination of many structural parameters of tissues; the methds are covered by the term stereology and are based on statistical sampling techniques introduced by geologists and materials scientists. Methods for determining the volume fractions of various compartments within a cell or tissue are presented, together with methods for determination of surface area, surface-to-volume ratio, and particle size and size distribution. The problems involved in applying these methods to tissue sections are discussed, together with the problems arising from anisotropy within the tissues. Sampling methods and test systems in common use are described and discussed in relation to available counting and recording systems, and the potentialities of automatic image analysing equipment in this field are assessed. A discussion of shape recognition follows, with a survey of recent stereological work.