ABSTRACT
Micrometry is the measurement of microorganisms. Since microorganisms can only be seen under a microscope, a suitable scale for their measurements should be located somewhere in the microscope itself. For this, an ocular micrometer serves as a scale or rule. An ocular micrometer consists of disks of glass upon which lines are etched. There are in general use two practical methods of measuring microscopic objects: (1) by means of the ocular micrometer and (2) by means of camera lucida sketches. The latter method is the best one for measuring spores and bacterial size in taxonomy (Figure 2.1a and b).
