424 RESEARCH IN PROTOZOOLOGY 



much the unsensitized organisms (without immune serum) are 

 phagocyted by the leucocytes. 



MISCELLANEOUS SEROLOGICAL TESTS 



A great deal of interest has been aroused in the past few years 

 by certain tests in kala-azar. Thus, Brahmachari (1917) noted 

 that the addition of distilled water to serum from kala-azar 

 cases resulted in the formation of a copious precipitate which 

 was globulin in nature and from which he devised his so-called 

 serum globuHn test for the disease. Ray (1921), in using a 

 hemoglobinometer, noted that with ])lood from kala-azar pa- 

 tients a cloudiness developed, which he thought was due to in- 

 complete hemolysis of the red cells (hence his name, "hemolytic 

 test"), but which later work showed came from the serum and 

 was also globulin. (See Sia and Wu's, 1921, work on the globulin 

 precipitation test.) Hill (1913) had probably observed the same 

 phenomenon in making leucocyte counts. Gate and Papacostas 

 (1920) devised what they termed the "formol gel test" for syphilis ; 

 this consisted in adding two drops of commercial formalin 

 to one cubic centimeter of clear serum, whereupon syphilitic 

 serums formed a hard gel within twenty-four to thirty hours 

 and normal serums did not. In applying this test to kala-azar, 

 Spackman (1921) found that the serum not only jelled within 

 a few seconds, but became opaque. This opacity is described by 

 Napier (1922) as resembling coagulated white of Ggg.^ Still 

 another flocculation test, i.e., the antimony test, was suggested by 

 Chopra, Gupta and David (1927), who found that a copious pre- 

 cipitate was formed when kala-azar serum was brought in con- 

 tact with antimony derivatives, especially urea compounds. 

 Furthermore, Napier (1927) found that the efficacy of a number 

 of pentavalent antimony compounds varied directly with their 

 therapeutic efficiency. All of the tests seem to be dependent upon 



'The opacity needs to be stressed. Since the original test, which was 

 dependent on jellification alone, was found to be unreliable, some investi- 

 gators have likewise condemned the test in kala-azar. In doing this, they 

 overlook the fact that, although the procedures are similar in the two tests, 

 the criteria are different. To obviate this confusion, Napier has suggested 

 calling the kala-azar test the aldehyde test. Using his criteria, the test has 

 proved to be very specific for kala-azar, except for complications with 

 schistosomiasis. (Cf. Faust and Meleney, 1924.) 



