. 76 



If a man exhibits secondary syphilis, nothing can shake 

 our conviction that he has, whether consciously or not, 

 come into contact, mediate or immediate, with a syphil- 

 itic person, although the sufferer himself may be honestly 

 unable to point out the moment or the mode of possible 

 infection. In many cases of pyaemia and diphtheria the 

 course of the infection is as plain as the track of the 

 lightning ; the effect as pronounced and almost as sud- 

 den as that of the murderer's bullet. In other cases, 

 however, of pyaemia, diphtheria, as well as of anthrax, 

 syphilis, and tuberculosis, there are absolutely no phe- 

 nomena observable in the individual which attract atten- 

 tion to a given moment as the time at which an infec- 

 tion, subsequently manifested, may have occurred. A 

 piece of tuberculous matter introduced into a rabbit's 

 eye may entirely disappear ; and for weeks the animal 

 presents absolutely no signs, local or general, of tuber- 

 culous infection. 



The opportunities for the usual mode of infection by 

 syphilis are only occasional ; and the attendant circum- 

 stances are such as to impress such occasions upon the 

 mind and conscience ; when, therefore, the first evidence 

 of infection appears, perhaps weeks subsequently, upon 

 that part of the anatomy peculiarly exposed upon such 

 an occasion, it is but natural that the mind should asso- 

 ciate the two phenomena as cause and effect. Were 

 syphilis communicated not in the way at present in 

 vogue, but by inhalation; were the initial evidence of 

 infection not upon the integuments and therefore visible, 

 but in the lungs and hence inaccessible to the eye, there 

 might be the same clinical grounds for doubting the in- 

 fectiousness of syphilis as of tuberculosis. The occurrence 

 of infection in tuberculosis is usually as unobserved clin- 

 ically as in the exceptional cases of syphilis, in which 

 a primary lesion was neither suspected nor discoverable. 



Another argument often heard against the infectious- 

 ness of tuberculosis, recently uttered and printed by 

 a Philadelphia surgeon, is the fact that we do not all 

 die of this disease. Yet the same argument is valid 



