318 IMMUNOLOGICAL METHODS OF DIAGNOSIS 



in a remarkably large percentage of cases quite early in the disease, 

 and that the cerebrospinal malady is most refractory to treatment 

 when once the disease has gained a foothold in that district, even 

 though it may have been eradicated elsewhere in the body. 



As regards the relation of the Wassermann reaction to the treat- 

 ment of syphilis with salvarsan or salvarsan in combination with 

 mercury, the majority of syphilographers are in accord in demanding 

 that the treatment be continued until a permanently negative 

 Wassermann is obtained and maintained (see section on Salvarsan). 

 This stand-point is in accord with the view that the Wassermann 

 reaction is a reaction of infection and not of immunity, and that the 

 existence of infection may be inferred so long as the reaction is 

 demonstrable (see also preceding paragraph). 



The rapidity with which the reaction disappears under treatment 

 is quite variable. I have thus obtained a persistingly negative 

 result after a single injection of salvarsan, while in other cases the 

 salvarsan in itself, though given repeatedly, was not able to cause 

 the reaction to disappear, whereas this promptly occurred, if mer- 

 curial treatment was instituted in addition. For further details of 

 this order, however, I must refer the reader to special works. 



In this connection it is interesting to note that Noguchi has 

 recently compared the findings obtained with the Wassermann 

 technique, i. e., with the use of lipoid antigen, with the results 

 which w r ere obtained, when a pure culture of spirochetes was used 

 as antigen. I append some of the more important conclusions to 

 which these investigations gave rise: "(1) The Wassermann reac- 

 tion is caused by lipotropic substances, but not by the antibodies 

 which combine specifically with the pallida antigen; (2) the fixation 

 produced by the culture pallida antigen with certain syphilitic sera 

 is caused by the specific antibodies contained in the latter and may 

 constitute a specific diagnostic method for syphilis; (3) the fixation 

 caused by a syphilitic testicular extract behaves like the culture 

 pallida extract in the majority of cases, but when the sera (syphilitic 

 or leprous) contain abundant lipotropic substances, it may give a 

 Wassermann reaction as well, which is not the case with the culture 

 pallida antigen; and, finally, (4) in the serum of rabbits with active 

 syphilitic orchitis there is no indication of the presence of a suffi- 

 cient amount of the antibodies for the pallida antigen, although 

 it gives a strong Wassermann reaction. It remains to be seen when 



