MODIFICATIONS OF THE WASSERMANN REACTION 457 



MODIFICATION OF HECHT-WFJNBFJIG 



In conducting the syphilitic reaction Hecht l utilizes not only the 

 natural antisheep amboceptor in human serum, but also the native 

 hemolytic complement. The serum must be perfectly fresh, and, of 

 course, is used unheated. This modification has been said to be more 

 delicate than the Wassermann reaction, because none of the syphilis an- 

 tibody is destroyed or complementoids produced, as, presumably, will oc- 

 cur during inactivation (heating) of a serum. In my experience, this test 

 has proved quite delicate, but is open to the same error that may occur 

 whenever an active serum is used, with a crude alcoholic organic extract 

 as antigen i. e., the appearance of false positive or proteotropic reac- 

 tions. As with the Noguchi reaction, using active serum, a negative 

 Hecht-Weinberg test has considerable diagnostic value in excluding 

 syphilis; a positive reaction must be, however, carefully controlled. 

 In performing the test I always use an extract of acetone-insoluble 

 lipoids as antigen. 



The Hecht test is performed as follows: An alcoholic extract of human heart is 

 used as antigen. Each serum is tested in four small tubes. The serum must be 

 fresh (not over twenty-four hours old) and unheated. 



Tube 1 : 0.02 c.c. serum (1 drop) and 0.08 c.c. (4 drops) of 1: 50 dilution of heart 



extract. 



Tube 2: 0.02 c.c. serum and 0.08 c.c. of 1: 100 dilution of heart extract. 

 Tube 3: 0.02 c.c. serum and 0.08 c.c. of 1: 200 dilution of heart extract. 

 Tube 4: 0.02 c.c. serum and 0.08 c.c. of normal salt solution. This is the one 



control of the test and should show complete hemolysis. 



The tubes are placed in the incubator for half an hour, or into a water-bath at a 

 temperature of 37 C. for ten minutes. One cubic centimeter of a 1 per cent, suspen- 

 sion of sheep's cells is added to each tube, and the tube shaken gently and reincubated 

 for half an hour or ten minutes, as the case may be. 



Tube 4 must show complete hemolysis; if it does not do so, the test is worthless. 

 In the test of a strongly positive acting serum all the other tubes show no hemolysis, 

 whereas a weakly acting serum -shows lysis in all tubes but Tube 1. 



This test is exceedingly simple, but is somewhat crude and unre- 

 liable. If employed at all, the results should always be controlled by 

 the Wassermann reaction. 



It is necessary to avoid using too large doses of sheep's cells. Since 

 in the test just described, there is no way of determining beforehand the 

 amount of corpuscles a serum may hemolyze, Gradwohl 2 has modified 

 the technic so that, the hemolytic index of each serum is determined 

 before corpuscles are added to the main tubes. His method is as follows : 



"Place in a rack 14 small test-tubes. The first 10 of these tubes are used to 

 determine the hemolytic index of the suspected blood. By this we mean the ex- 

 act amount of hemolytic amboceptor present in the given blood-serum. The last 



1 Wien. klin. Wochenschr., 1909, xxii, 265. 



2 Jour. Amer. Med. Assoc., 1914, Ixiii, 240. 



