432 RESEARCH IN PROTOZOOLOGY 



Pewny (1918) first obtained precipitins in malaria with a test 

 antigen prepared from heavily parasitized blood clots (placenta?). 

 These were digested in distilled water at 37° C. for 5-6 days, 

 centrifnged and filtered. The present author has been associated 

 with two studies of precipitins in malaria (W. H. and L. G. 

 Taliaferro, and Fisher, 1927, and W. H. and L. G. Taliaferro, 

 1928). The most efficient test antigen was obtained by con- 

 centrating the parasites from a heavily infected placenta by cen- 

 trif ugation ; these, either dried or fresh, were extracted in ether ; 

 and the wet residue was extracted in Coca's solution, filtered 

 and adjusted to pH 7.8 before use. Some work was also carried 

 out by extracting 0.65 gm. dried powder for from ten to twenty 

 hours in from one and one-half to two cubic centimeters N/20 

 HCl made up in saline, and adjusting the supernatant to pH 

 7.8 before use. 



E. Coccidiosis. Although a number of the earlier workers felt 

 that coccidiosis in the rabbit incited the formation of Wassermann 

 reagins and might thus explain why so many "normal" rabbits 

 were Wassermann positive, more recent work indicates that with 

 carefully controlled technique coccidiosis of the rabbit does not 

 lead to positive Wassermann tests (Marcuse, 1922). 



Specific complement fixation was considered of no diagnostic 

 value by Marcuse (1922) but of considerable value by Patterson 

 (1923) who found normal saline extracts of infected livers to be 

 best. Chapman (1929) did not obtain very high titres although 

 she felt that the test was probably specific. The most satisfactory 

 test antigen was prepared by shaking a heavily infected minced 

 rabbit-intestine in fifty cubic centimeters of distilled water plus 

 0.5% phenol for two hours, leaving at room temperature two 

 days, adjusting to isotonicity with NaCl, centrifuging and filter- 

 ing. 



It is impossible to decide whether these variable results are 

 due to lack of an efficient antigen or to lack of antibody formation. 

 Prof. G. W. Rachman (unpublished work) has succeeded in pre- 

 paring a powder of pure Enne?'ia from rabbits by digesting away 

 the muscle fibers in pepsin and hydrochloric acid and getting rid 

 of remaining yeasts by a differential flotation with a sugar solution, 

 then washing and drying. He has found only weak precipitin 

 reactions, but the benzoin floculation test of de la Riviere (1929) 

 gives considerable promise. 



