Stain for treponema ?

Ans. is 'a' i.e., Fontana's Can not be seen under light microscope in wet films but can be made out by negative staining with India ink. L pallidum does not take ordinary stains, but stain light rose red with prolonged Giemsa staining. Morphology and motility can be seen under the dark ground or phase contrast microscope. It can be stained by silver impregnation methods. Fontana's method is useful for staining films. Levaditis's method for tissue sections.