An immense amount of work has been done in the last eleven months on the etiology of syphilis, work that very probably will mark an epoch in our knowledge of that scourge of the human race. It seems worth while to review briefly what has already been accomplished.
Lassar calls attention to the fact that more than twenty-five causes of syphilis have been described during the last thirty years. As early as 1837, Donné described a parasite found in syphilitic ulcers and named it Vibrio lineola. In 1902, Bordet and Gengou found spirochetes in chancres and throat lesions, but discontinued their researches when they did not find the organisms constantly.Early in 1905 Siegel observed actively motile flagellate bodies in enormous numbers in the blood of several syphilitics and named them Cytorrhycetes luis. Schaudinn had earned a reputation in the study of protozoa, malarial parasites, trypanosomes, etc., and