514 INFECTION AND RESISTANCE 



with normal sera. This Fornet 163 in a number of communications 

 interpreted as showing the formation of precipitins in the course of 

 syphilis. At almost the same time, L. Michaelis 164 made similar 

 observations giving them the same interpretations. The experiments 

 of Fornet have not found universal confirmation, but even if such 

 precipitin reactions can be occasionally observed, they do not indicate 

 true precipitins for the same reasons that the Wassermann reaction 

 does not demonstrate true complement fixation of antibodies. The 

 antigens did not represent strong treponema antigens and Jacobs- 

 thai 165 and others have shown that with the ordinary Wassermann 

 antigens syphilitic sera can produce precipitations visible under the 

 dark field, the basis of the complement fixation being, therefore, one 

 of probable colloidal precipitation. The formation of true precipi- 

 tins, therefore, has not been shown for syphilis. 



Investigations of the effect produced upon virulent treponemata 

 by the sera of syphilitic individuals have likewise been unsatisfac- 

 tory. Hoffmann and Prowazek 166 reported in 1906 that the serum 

 of syphilitics in the later stages produced immobilization of the 

 virulent treponema pallidum, an observation which was confirmed 

 by Zabolotny. 167 Landsteiner and Mucha 168 were not able to observe 

 such immobilization, nor did they see any evidence of agglutination 

 in such experiments. In a limited observation of our own, we have 

 also failed to see any regular or distinct influences of this kind. It is 

 not impossible that a slight difference may exist in this respect 

 between syphilitic and normal sera, but even if it occurs, the action 

 is feeble, irregular, and entirely insufficient to be interpreted as 

 having much practical importance in the acquisition of syphilis 

 immunity. 



Treponemacidal experiments have been done by some workers 

 also with negative results. As we have stated in another part of 

 this paper, the attempt to treat syphilitic animals and man with the 

 serum of syphilitics has led to no reliable results, and no evidence 

 whatever that can be accepted has been adduced to show that virulent 

 treponemata may be killed by active luetic serum. 



As far as any opsonic action is concerned, Levaditi 169 in histo- 



163 Fornet, Schereschewsky. Munchen med. Wchnschr., 1907, No. 30 ; 

 Berl klin. Wchnschr., 1908, 85. 



164 Michaelis. Berl. klin. Wchnschr., 1907, No. 46. 



165 Jacobsthal. Munchen. med. Wchnschr., 1910, Ivii, 214. 



166 Hoffmann, E., and Prowazek, S. Centralbl f. Bakteriol, I. 0., 1906, 

 xli, 741 and 817. (Balanitis and montu spirochaetae.) 



167 Zabolotny, D., and Maslakowitz. Centralbl f. Bakteriol, I. O., 

 xliv, 532. 



168 Landsteiner and Mucha. Wien klin. Wchnschr., 1906, xix, 1349; Cen- 

 tralbl f. Bakteriol, 1907, I. R., xxxix, 540. 



169 Levaditi. Compt. rend. Soc. de biol, 1906, Ix, 134; Ann. de I'Inst. 

 Pasteur, 1906, xx, 41. 



