524 SYPHILIS 



that this gives a characteristic cutaneous reaction in syphilitics. 

 This reaction is analogous to the tuberculin reaction in tuber- 

 culosis, and like it depends on a condition of super-sensitiveness 

 or allergy (p. 595). In a normal individual the intradermic 

 inoculation of luetin produces a local erythema which may 

 sometimes go on to the formation of a slight papule on the 

 second day; thereafter the reaction recedes. In the case of 

 syphilitics Noguchi distinguishes three types of positive re- 

 action (a) papular form, in which a large indurated, reddish 

 papule, 5-10 mm. in diameter, forms and increases for three or 

 four days, the colour becoming dark bluish red; (b) pustular 

 form, in which the inflammatory change is more severe, the 

 papule changing into a vesicle and then into a pustule ; and 

 (c) torpid form, in which, after a latent period of about ten 

 days, reaction appears and goes on to the formation of a small 

 pustule. Noguchi's claims as to the specificity of the reaction 

 are supported by the observations of Cohen in ophthalmic cases 

 and of Orleman Robinson in cases of skin disease. The results 

 obtained so far show that a positive result is got when the 

 disease is of long standing or comparatively inactive in the 

 tertiary stage, in latent and congenital syphilis a positive 

 luetin reaction being obtained in such conditions in a larger 

 proportion of cases than a positive Wassermann reaction. It is 

 often absent in secondary syphilis, but may appear after anti- 

 syphilitic treatment has been carried on for some time. 



Serum Diagnosis Wassermann Reaction. The method of 

 applying this test has already been given (p. 132) ; we have now 

 to consider the results of its application. There is general 

 agreement amongst workers at the subject that the test affords 

 by far the most reliable means of diagnosis of the disease ; and 

 on comparing the results obtained it will not be an overestimate 

 to say that a positive result may be obtained in at least 90 per 

 cent, of cases where there is evidence of active general infection. 

 The reaction generally appears first on the fifteenth to thirtieth 

 day after appearance of the sore, and then gradually becomes 

 more marked ; during the period of secondary manifestations it 

 is practically always present ; in the tertiary stage with active 

 manifestations a positive result is only a little less frequent. As 

 the disease becomes inactive or is cured the reaction may disappear, 

 but it is to be noted that disappearance of the reaction after being 

 present does not necessarily imply cure of the disease. It may 

 only have become latent, and on its becoming once more active 

 the reaction may reappear. Energetic treatment with mercury 

 may also diminish or annul the reaction ; in fact, its presence 



