CHAPTER XXIV 
THE SPIROCHETAL DISEASES 
Spirochetes or treponemata belong to a class which is 
half way between the true bacteria and protozoa (the 
lowest order of animal). They are corkscrew-like, wavy 
threads. Several very important diseases are caused by 
the various spirochetes. (See Fig. 40.) 
I. Syphilis 
Syphilis, probably, is the most disseminated disease, 
transmitted by direct contact, sexual or asexual, caused 
by Spirocheta pallida, discovered by Schaudinn and 
Hoffmann in 1905. It must be stained by special method, 
not to be attempted by the beginner, and can be grown 
anaerobically on ascitic fluid agar to which a piece of 
sterile rabbit kidney has been added. Noguchi, of the 
Rockefeller Institute, is the discoverer of this method. 
One of the simplest methods of staining is to place a 
drop of material from a syphilitic lesion on a glass slide 
and mix it with a drop of India ink, then make a smear 
as if a blood smear is to be made. Examined with the 
oil-immersion lens the spirochetes appear unstained 
against a black background. 
Within a year of the discovery of the Spirocheta pal¬ 
lida, Wassermann, Neisser and Brack devised a special 
test known as the “Wassermann test,” which shows the 
presence of the disease, even though no symptoms or 
signs are detected. 
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