<unk>  <unk>  Ground Microscopy) is an optical microscopy illumination technique used to enhance the contrast in unstained samples. It works on the principle of illuminating the sample with light that will not be collected by the objective lens, so not form part of the image. This produces the classic appearance of a<unk> , almost black, background with bright objects on it.
Dark field microscopy
Fluorescent treponemal antibody absorbtion 
Microscopy
Silver stain
Latex fixation test
Spectrophotometry
Direct fluorescent antibody
Kato-Katz thick smear