420 PHENOMENON OF COMPLEMENT FIXATION 



fix complement with various lipoidal and bacterial antigens in a non-specific 

 manner. Schilling and Hoesslin 1 were probably among the first investi- 

 gators to note this phenomenon with normal rabbit serum. Manteufel 

 and Woithe 2 and Browning and McKenzie 3 have also noted the phenom- 

 enon during studies in experimental trypanosomiasis. Dohi 4 examined 

 the sera of 74 normal rabbits, using as antigen an alcoholic extract of 

 syphilitic liver, and found that 39 reacted positively and 35 negatively. 

 He also observed that heated serum was more likely to show this non- 

 specific absorption of complement than unheated serum. Browning and 

 McKenzie, however, state that they have not observed this phenomenon 

 when using serum in a fresh, or active, condition. Blumenthal 5 has like- 

 wise observed positive reactions with normal rabbit serum, using an 

 alcoholic extract of syphilitic liver as antigen; Craig and Nichols, 6 on the 

 other hand, have reported uniformly negative results with an alcoholic 

 extract of syphilitic liver. Similar observations on this power of normal 

 rabbit serum to absorb complement in the presence of lipoidal antigens 

 have been made by Emmanuel 7 and by Epstein and Pribram, 8 the former 

 stating that the administration of salvarsan removes this propertj^ 

 temporarily, and the latter making similar claims for the mercurials. 

 Casselman and I 9 observed a large percentage of positive reactions with 

 the sera of 117 normal rabbits and various lipoidal extracts used as 

 antigens in the Wassermann reaction. In a further study by Miss Trist 

 and I 10 we found that while heated rabbit serum yielded positive re- 

 actions with 38 to 49 per cent, of sera with lipoidal antigens, active or 

 unheated sera yielded but 5-15 per cent, positive reactions. Bacterial 

 antigens yielded even higher percentages of positive reactions. Pearce 

 and I 11 have also found that the sera of animals reacting positively or 

 negatively generally continue to react in the same manner over long peri- 

 ods of observation. Rossi, 12 Miss Trist and I 13 have also found that the 

 sera of a large percentage of normal dogs tends to yield non-specific fixa- 



1 Deutsch. med. Wchnschr., 1908, 34, 1422. 



2 Centralbl. f. Bakteriol., R., 1909, 43, 359. 



3 Jour. Path, and BacterioL, 1909-11, 15, 182. 

 4 Beitr. z. path. u. Therap. der Syph., 1911, 514. 



5 Berl. klin. Wchnschr., 1911, 48, 1462. 



6 Jour. Exper. Med., 1911, 14, 206. 



Berl. klin. Wchnschr., 1911, 48, 2335. 



8 Ztschr. f. exper. Path. u. Therap., 1909, 7, 549. 



9 Jour. Med. Research, 1913, 28, 369. 



10 Jour. Infect. Dis., 1916, 18, 20. u Jour. Infect. Dis., 1916, 18, 32. 



12 Ztschr. f. Immunitatsf., R., 1909, 1, 429. 



13 Jour. Infect. Dis., 1916, 18, 27. 



