i 3 6 



MICROMETRY AND BLOOD PREPARATIONS. 



and is the i/iooo part of a millimeter. There are 1000 mikronsina 

 millimeter. 



To standardize: For this purpose it is necessary to have a scale 

 of known measurements. The stage micrometers are usually ruled 

 in spaces of .1 and .01 mm. The lines which are i/io of a millimeter 



FIG. 48. Micrometry diagrams, i. Ocular micrometer with stage micrometer. 

 50 spaces of ocular micrometer cover two 100 micron spaces and ten 10 micron 

 spaces; equal 300 microns. Each division on ocular micrometer equals 6 microns. 

 2. Ocular micrometer subtending image of whip worm egg. 9 spaces of ocular 

 micrometer cover Whipworm egg. Each space equals 6 microns. Whipworm egg 

 equals 54 microns. 3. Ocular micrometer with ruling of hasmacytometer. 50 spaces 

 of ocular micrometer cover space equal to width of 6 small squares 50 x 6 = 300 

 microns. Each division of ocular micrometer equals 6 microns. 



apart are consequently separated by a distance of loomikrons; those 

 i/ 100 of a millimeter apart are separated by a distance of 10 mikrons. 



The ocular micrometer is usually ruled with 50 or 100 lines or 

 spaces, separated by longer lines into groups of 5 and 10. 



Having brought the lines on the stage micrometer to a focus, we 



