FIG. A. Spirochaeta pallida and Spirochaeta refringens. Smear 

 from a primary syphilitic sore, fixed in osmic vapour and stained by 

 Giemsa's method (leucocytes necessarily overstained) . 



I 





FIG. B. Spirochaeta pallida in liver of syphilitic foetus. Stained by 

 Levaditi's silver method. 



