516 INFECTION AND RESISTANCE 



duced in high potency by the writer with Hopkins. Subsequently 

 in our own laboratory with Hopkins and McBurney, extensive ex- 

 perimentation on the production of antibodies with culture pallida 

 was carried out. 



We were able to show that not only were agglutinins formed by 

 the immunization of rabbits with such cultures, but also that tre- 

 ponemacidal antibodies which were analogous to the ordinary bac- 

 tericidal substances in such sera were present. Also, it was shown 

 by cross agglutination and absorption experiments, that treponemata 

 cultivated from various sources were related in group reactions. 



Indeed, experiments done with cultivated treponemata (much 

 facilitated by the discovery of a simple method of obtaining mass 

 cultures of old strains) seemed at first very encouraging in that 

 animals immunized with the cultures responded by powerful anti- 

 body formation. It was a perfectly justified hope, therefore, that 

 antibodies produced with these "attenuated" or rather "avirulent" 

 strains might have some action on the virulent treponemata in luetic 

 lesions. However, subsequent work in this direction disappointed 

 such expectations. We may briefly review this work as follows : 



The serum of rabbits immunized with "culture" pallida although 

 potent against "culture" pallida, had no effect either in agglutinating 

 the virulent organism from rabbit lesions, nor did it exert any pro- 

 tective influence when the virulent organisms were subjected to its 

 action before injection. 4 



Conversely, the serum of syphilitic rabbits showed but a very 

 slightly increased agglutinating power for the "culture" pallida. 

 This increase of potency in a few experiments was definite but very 

 slight, a few of the syphilitic animals agglutinating as highly as 1 :25 

 and 1 :50, whereas most of the normal rabbits agglutinated in 1 :10 

 and some of them 1 :25. 



Although Kissmeyer has recently reported that diagnostic use 

 might be made of the fact that sera of syphilitic individuals ag- 

 glutinated the "culture" pallida, we have tried this with a consider- 

 able number of cases and found that although the sera of tertiary 

 syphilitics will sometimes agglutinate a little more highly than will 

 the sera of normal individuals, yet many patients suffering from 

 non-syphilitic diseases agglutinated as highly and almost as regularly 

 .as did the syphilitics. 



We have come to the conclusion, therefore, as far as our work 

 lias gone, that in the syphilitic human being there is as little ag- 

 glutinin formation against the "culture" treponema as there seems 

 to be against the virulent organisms. If the slightly greater ag- 

 glutinating power found in some of the tertiary syphilitics can be 

 considered at all, the reaction is so feeble that it is negligible from 

 the points of view either of diagnostic value or protective importance. 



Furthermore, vaccination either intravenously or locally into the 



