THE RELATION OF LIPOIDS TO IMMUNITY 553 



watery extract of a normal or a diseased organ. This view is supported 

 by the fact that euglobulin is known to be generally increased in the 

 body fluids of syphilitics, and by analogy with the various precipitin tests 

 that have been devised for the diagnosis of syphilis, as, for example, the 

 reaction of Forges and Meier, which is dependent upon the appearance 

 of a precipitate when luetic serum is mixed with an emulsion of lecithin 

 or sodium glycocholate, etc. The exact nature of the antibody in 

 syphilitic serums that forms these new compounds with lipoids and 

 complement, resulting probably in the absorption of complement, is 

 unknown. It is most likely in the nature of a globulin, its main char- 

 acteristic being the power it possesses of reacting with lipoids. Schmidt l 

 ascribes the reaction to the physicochemical properties of the globulins 

 of the syphilitic serum, which he believes possess a greater affinity for 

 the colloids of the antigen than do normal globulins. This view is 

 supported by the common observation that the turbidity of the antigen 

 emulsion is closely related to its efficiency, since clear solutions are less 

 active. Since various lipoidal substances may be employed, the Was- 

 sermann reaction can not be regarded as specific in the immunologic 

 sense, although practically it is highly specific, as similar conditions are 

 to be found in only two other diseases with any degree of regularity, 

 namely, frambesia and tuberous leprosy. 



THE RELATION OF LIPOIDS TO IMMUNITY 



It is becoming more and more evident that lipoids bear an important 

 relation to various immunologic processes, especially to certain cytolytic 

 phenomena. 



As stated in Chapter VIII, the results of some researches that go to 

 show certain lipoids and lipoidal substances may act as true antigens 

 and produce antibodies. 2 This, however, has not been definitely proved, 

 and while it is of great importance, is not necessarily pertinent to the 

 subject in hand. As the relation of lipoids to various immunologic 

 processes has frequently been described in earlier chapters, as, e. g., 

 where the role of lipoids in venom hemolysis, in the Wassermann syphilis 

 reaction, and in the various precipitin reactions in syphilis were con- 

 sidered, a brief resume* may be of service in directing attention to this 

 important and particular phase of immunity. 



1 Zeit. f. Hygiene, 1811, 69, 513. 



2 Bibliography on Lipoids and Immunity given by Landsteiner, Kolle and 

 Wassermann's Handbuch, 1913, 2, 1240. Also review of literature by Landsteider, 

 Jabresb. Immunitat, 1910, 6, 209. 



