A STUDY OF FIXATION REACTIONS. 371 



The diagnostic value of the test has already been very great to the 

 clinician, the surgeon and neurologist, and to other specialists, and 

 Proskauer professes to employ it as a routine autopsy procedure. 



The former article of MarshalK 1 ) showed that there was considerable 

 discussion over the theoretical interpretation of this reaction. Wasser- 

 mann's idea that it indicated the union of syphilitic antigen with 

 syphilitic antibody at first found almost universal acceptance. 



However, Michaelis(23) very soon pointed out that the differences observed in 

 the action of syphilitic serum toward syphilitic liver extract and toward normal 

 liver extract were quantitative rather than qualitative. Then it was shown, 

 as has been mentioned, that syphilitic serum gave positive reactions with extracts 

 of normal organs, with lecithin and with sodium oleate and when comparative 

 tests were made these substances yielded practically the same percentage of 

 positive results as were obtained with the extracts of syphilitic liver. Hence 

 the idea that the reaction was concerned with syphilitic antigen and antibody 

 had to abandoned. Elias, Neubauer, Porges, and Salomon (24) regard the reac- 

 tion as a precipitation reaction between colloids, the proteins of syphilitic serum 

 having greater instability and yielding a wider flocculation zone than non- 

 syphilitic serum with certain hydrophilic colloids, such as extracts of organs, 

 lecithin, sodium oleate, and scdium glycocholate. 



Although the reaction is not specific in Ehrlich's use of the term, yet 

 almost all observers agree that it has a high degree of clinical specificity. 



Weil and Braun(25) report positive findings in pneumonia, typhoid, tuber- 

 culosis, diabetes, and malignant growths, but their results have not been con- 

 firmed by others. Much and Eichelberg(26) obtained positive reactions in 4Q 

 per cent of the scarlet fever patients subjected by them to the test. Seligmann 

 and Klopstoek(27), Hoehne(28), and Schliessner(29), however, report only neg- 

 ative results in scarlet fever. Weehselmann and Meier(30) and Eitner(3l) 

 obtained positive results in two cases of leprosy. 



In contrast to the above exceptions, to which a few others could be 

 added, the general verdict is that Wassermann's sero-diagnosis of syphilis 

 is clinically specific. 



We have thus far considered- the application of the deflection of 

 complement to the diagnosis of syphilis and to the differentiation of the 

 blood of various species of animals. On treating the extract of bacteria 

 with the serum of an animal immunized against the same bacteria, 

 deflection of complement is likewise produced and the application of 

 this principle bids fair to furnish an important addition to bacteriologic 

 technique for the differentiation of closely related microorganisms. 



The attempts of Ballner and ReibmajT(32) to differentiate the capsule bacteria 

 and of Gengou(33) to distinguish between the acid fast bacilli by this method 

 were unsuccessful. Schiitze(34) concluded that the method was of no value in 

 the study of cholera-like organisms, whereas Ruffner(35) claimed that it enabled 

 him to differentiate between the strains of El Tor and of true cholera and was 

 hence more delicate than the agglutination test. Leuchs(36) could distinguish 

 between typhoid, paratyphoid and the colon bacillus and Vannod(37) between 



