360 MARSHALL AND TEAGUE. 



4. Wassermann and Citron(7) have shown that albumoses, glycogen, fatty 

 stuffs, and lecithin block complement in even small doses. The richer a fluid 

 is in colloidal materials, the more it deflects and vice versa. Extracts of red 

 blood corpuscles deflect most; spinal fluid, least. As a rule, fresh red blood 

 corpuscle extract does not deflect in a dose of 0.5 cubic centimeter; old extracts 

 deflect in doses no larger than 0.1 cubic centimeter. These various effects 

 are distinct from the specific deflection. 



.Miiliaelis and Lesser(4) find that occasionally an extract of syphilitic liver is 

 itself hemolytic when added to corpuscles, amboceptors and complement. Fur- 

 thermore, a definitely deflecting serum will often suddenly lose its power after 

 standing. 



Meier(3) finds that antibody loses strength upon being kept even in completely 

 filled, tightly sealed and blackened tubes in a. cold place. Its action also varies 

 with the age and condition of the complement and of the red blood corpuscles. 

 Wassermann(2) notes that upon standing, even a perfectly clear serum or extract 

 gradually develops a cloudiness or even a slight precipitation. It is very neces- 

 sary to centrifugate both serum and extract until they are perfectly clear before 

 performing the experiment. The slightest trace or precipitation in the serum 

 makes it unavailable for the experiment. It must be remembered, however, that 

 each centrifugation of a serum or extract decreases its strength, it appearing 

 that the active constituents are carried down in the sediment. 



2. Preliminary Experiments. 



a. complement. 



Most observers, including Wassermann(2), Michaelis(4), and Meier(3) recom- 

 mend the use of 1 cubic centimeter of a 0.1 dilution of guinea-pig serum, as the 

 standard amount of complement for use in each test. 



B. VALUE OF HEMOLYTIC AMBOCEPTOR. 



With each amboceptor a test must be made at the outset to determine ap- 

 proximately its value. This value remains fairly constant, but shows gradual and 

 progressive deterioration. Before each experiment make a preliminary test with 

 0.1 cubic centimeter of guinea-pig serum to determine whether the hsemolytic 

 amboceptor retains its strength. 



Meier (3) simplifies this experiment as follows: He heats diluted fresh comple- 

 ment for one hour at 37°, so that the results obtained will be comparable with 

 those in the rest of the experiment; he then prepares three test tubes with fixed 

 amounts of corpuscles and the heated complement, and dilutions of 1.5, 2 and 3 

 of the amount of the hemolytic amboceptor which proved satisfactory in the 

 previous experiments. Thus, if in a previous experiment 1 : 200 of amboceptor 

 gave a good deflection, the dilutions of hemolytic amboceptor tried out in the 

 preliminary experiment will be 1 : 300, 1 : 400, and 1 : 600. He examines this 

 preliminary test after fifteen minutes, thirty minutes, one and two hours. In 

 the first tube he expects to find lysis after thirty minutes, in the second in one 

 hour at the latest, in the third it should be almost complete in two hours. After 

 the first two tubes are positive, he estimates the dose of amboceptor which will 

 be required and continues with the deflection experiment without delay. 



C. ANTIGEN. 



Meier (3) notes that it is very necessary to test the value of the antigen and to 

 employ fresh serum from an unquestionably syphilitic patient in making the 

 test. If the syphilitic serum is not fresh it may deflect with an extract of 



