PRECII'ITIX TKSTS IN SYPHILIS 463 



lioiir ill a Wassermann rack. Unaltered sediment is positive, while 

 tlie reaction is negative if the sediment has run down the side of 

 tlie tube. 



Hinton Test.— Hinton Antigkx.— This test is known as the sec- 

 ond modification of Hinton (1930, 1931, 1940). The reaction is a 

 macroscopic floccuhition test for reagin. Tlie lipoid extract con- 

 sists of the elher-insoliiblc, alcohol-soluble lipoids of beef heart 

 with 0.4 per cent cholesterol added. 



Glycerated Indicator Solution. — The antigen used in making 

 the test is called a " glycerinated indicator solution." A one 

 hundred c.c. Erlenmeyer flask that has a ridge across the bottom 

 dividing it into two equal compartments is used. 



The reagents used in preparing the antigen are : 



1. Cholesterolized beef heart extract. 



2. Salt-salicylic acid mixture containing 5 per cent sodium 

 chloride and 0.00222 per cent salicylic acid. 



3. Fifty per cent neutral glycerol (glycerol diluted with dis- 

 tilled water). 



Technique of Test. — One cubic centimeter of cholesterolized 

 antigen is placed on one side of the ridge and 0.8 c.c. of the salt- 

 salicylic acid mixture on the other side. The reagents are mixed 

 by rotating for one minute and allowed to stand at room tem- 

 perature for five minutes. Thirteen and two tenths c.c. more of 

 salt-salicylic acid mixture are added to the suspension in the 

 flask and after thoroughly mixing, 15 c.c. of the 50 per cent 

 glycerol solution are added. This makes a 1 :30 dilution of the 

 original beef heart extract. The indicator solution keeps one week 

 at ice box temperature. 



Serum is inactivated at 55° C. for thirty minutes. Five-tenths 

 c.c. each of serum and indicator are pipetted into a test tube 

 (10 mm. X 100 mm.). The rack is inclined at an angle of 45° and 

 shaken in such a manner that the liquid travels halfway up the 

 side of the tube with each forward thrust. The shaking period 

 is three minutes. 



The tubes are incubated in a 37° C. water bath for sixteen 

 hours. 



In the positive reaction there is a ring or band of course gran- 

 ules at the top of the tube, accompanied by complete clearing of 



