Of the various methods employed to establish the etiologic relation of Spirochæta pallida to syphilis, those concerned with its demonstration in syphilitic tissue have received comparatively little attention.
The first positive findings are reported by Berterelli and Volpinio,1 who examined the liver and spleen of children dying of hereditary syphilis. It was not until Levaditi, by modifying the Ramon y Cajal method for nerve fibers, formulated an exact staining method, that spirochetes were demonstrated in sufficient quantities to make it a valuable means of studying the organism within the tissue. His method is as follows: Small pieces of tissue about 2 mm. in thickness are hardened in formalin 10 per cent, for twenty-four hours, and then alcohol for the same period and subsequently washed in water for a short time. They are stained in a freshly made solution of silver nitrate 1.5 per cent, for three successive days, changing
UHLE AA, MACKINNEY WH. THE DEMONSTRATION OF SPIROCHÆTA PALLIDA IN LESIONS OF ACQUIRED SYPHILIS.. JAMA. 1907;XLVIII(7):605-607. doi:10.1001/jama.1907.25220330047002