A. 



unit #i +i unit #2a -f- I unit 

 unit #i +i unit #3+1 unit 



unit #1+1 unit #20 + I unit #4. 

 unit #2a + i unit #4. 

 unit #ab + i unit #4. 

 unit #3+i unit #4. 

 unit #4. 

 unit #i. 

 unit #2a. 

 unit #2b. 

 unit #3. 



The tubes receive first the solutions on the left and are placed 

 in the 37C. incubator for two hours to allow union of their various 

 parts, particularly the complement with others. They then re- 

 ceive the solutions on the right, are placed in the incubator for 

 half an hour and in the ice-box overnight, when they are ex- 

 amined for a solution of the red coloring matter. If it occurs, the 

 column is perfectly clear red with some residue of extracted cells. 

 If no hemolysis has occurred, the red cells form a layer at the bot- 

 tom, and the column is clear and colorless. 



A and B are the tests of syphilitic sera while the remaining are 

 to find out if the other solutions affect the results of A and B. Of 

 course tube G represents simply the complete hemolytic system. 

 The extra tests are to exclude the possibility of interference on 

 the part of any single member with the complement No. 4. The 

 character of the test is found in tube A where syphilitic antigen and 

 serum have bound or fixed the complement so that it cannot unite with 

 the rabbit serum and sheep's corpuscles to hemolyze the latter. This 

 is a positive test. A negative test is when hemolysis occurs, since no 

 anti-body is present to unite with complement in the presence of 

 antigen. 



Complement Deviation. This is a condition arising when there 

 is too much amboceptor and too little complement. The free 

 amboceptors adsorb complement and there is none left for cell 

 needs or renewed demands. It is to be distinguished from com- 

 plement fixation. The terms are not interchangeable. 



