476 THE SPIROCHETES 



triumph, revealing the exi'stence of a syphilitic infection without demonstrating 

 the organism itself, although the phenomenon proved not to be strictly specific for 

 this disease. Thus syphilis, not only in its usual manifestations, characterized clini- 

 cally as the primary, secondary, and tertiary stages, but also in its hereditary trans- 

 mission, is now well understood. The real syphilitic nature of so-called "metalues" 

 or "paras>T3hilis" was definitely established in 19 13.' 



Metschnikoff and Roux^ in 1903-4 had already transmitted syphilis to apes, and 

 soon after the discovery of the organism in human lesions they found it in experi- 

 mental syphiUs. Schultze,^ BertareUi/ and Parodi^ showed that syphilitic infection 

 could be produced in rabbits. For the purpose of maintaining strains of T. pallidum 

 the testicular mode of inoculation was formerly employed, but Brown and Pearce'' 

 have observed that the lymph nodes become involved early in the course of a syphil- 

 itic infection of the rabbit and remain infected almost indefinitely. Hata^ found Tomas- 

 czewski's scrotal chancre most satisfactory in chemotherapeutic experiments. Nichols 

 and Hough^ were the first to isolate a strain of T. pallidum from a rabbit with nervous 

 symptoms, the organism being recovered from the cerebrospinal fluid. Graves' suc- 

 ceeded in infecting rabbits by injecting the blood of paretic patients, and Marie, 

 Levaditi, and Banus'" subsequently confirmed the infectiveness of paretic blood. 



The etiological relationship between syphilis and paresis was suspected as long 

 ago as 1857" because of the frequency of syphilis in the history of paretic patients. 

 Ranke'^ and others demonstrated T. pallidum in the pia and vessel sheaths in con- 

 genitally syphilitic brains. Dunlap demonstrated the organism in a case of cerebral 

 syphilis. Moore and the writer'^ found the parasites in twelve of seventy-two paretic 

 brains stained by the Levaditi method (Fig. 90). They occurred in all layers of the cor- 

 tex save the outer or neuroglia layer; a few were found subcortically, but none in the pia 

 or vessel sheaths. Subsequently the writer studied one hundred and thirty other 

 paretic brains'-i and in thirty-six of the series was able to demonstrate the parasite by 

 the silver impregnation method. Darkfield examination of the fresh brain tissue was 



' Noguchi, H., and Moore, J. W.: J. Exper. Med., 17, 232. 1913; Noguchi, H.: Miinchcn. mcd. 

 Wchnschr., 60, 737. 1913. 



2 Metschnikoff , E., and Roux, E.: Ann. de I'lnsl. Pasteur, 17, 809. 1903; 18, i, 657. 1904; 

 19, 673. 1905; 20, 785. 1906. 



3 Schultze, W.: Med. Klin., i, 466. 1905. 



■t Bertarelli, E.: Centralbl.f. Bakteriol., \ht. I, 41, t,2i. 1906. 



5 Parodi, U.: ibid., 44, 428. 1907. 



^ Brown, W. H., and Pearce, L.: /. Exper. Mcd., 34, 185. 1921. 



' Ehrlich, P., and Hata, S.: Die cxperimcntellc Tlicrapie der Spirilloscn. Berlin, 1910. 



8 Nichols, H. J., and Hough, W. H.: J. A.M. A., 60, loS. 19x3. 



' Graves, W. W.: ibid., 61, 1504. 1913. 



"Marie, P., Levaditi, C, and Banus, G.: Compl. rend. Acad, sci., 170, 1021. 1920. 

 " Esmarch, F., and Jessen, W.: Allg. z. PsycliiaL, 14, 20. 1S57. 

 " Ranker Z. Erforsch. u. Behandl. jugendl. Scliwachsinns, 2, 32, 81, 211. 1909. 

 " Noguchi, H., and Moore, J. W.: loc. oil. 

 '■i Noguchi, H.: Munchen. med. Wchnschr., 60, 737. 1913. 



