350 STUDIES IN IMMUNITY. 



EXPERIMENT II. 

 Two large tubes are prepared. 



Tube A. Serum of ox, 55 degrees 0.05 c.c. 



Serum rabbit > ox, 55 degrees 2.00 c.c. 



Tube B. NaCl solution, 0.85 per cent 0.05 c.c. 



Serum rabbit > ox, 55 degrees 2.00 c.c. 



Contact, 2 hours. Tube A gives a dense precipitate; B, none. 

 Tube A is centrifugalized and the supernatant fluid used for the 

 following small tubes: 



Series A. Tube 1. Treated serum A 0.2 c.c. 



Tube 2. Treated serum A 0.1 c.c. 



Tube 3. Treated serum A 0.05 c.c. 



Tube 4. Treated serum A 0.025 c.c. 



Series B. Tube 5. Treated serum B 0.2 c.c. 



Tube 6. Treated serum B 0.1 c.c. 



Tube 7. Treated serum B 0.05 c.c. 



Tube 8. Treated serum B 0.025 c.c. 



Each tube is brought to the same volume (0.2 of a cubic centi- 

 meter) with salt solution, and then to each tube is added 



Washed ox corpuscles 0.05 c.c. (washed four times) 



Alexin of rabbit 0.05 c.c. 



Resultant hemolysis is as follows : 



Series A. Series B. 



Tube 1. Complete Tube 5. Complete 



Tube 2. Nearly complete Tube 6. Nearly complete 



Tube 3. Marked Tube 7. Marked 



Tube 4. Marked Tube 8. Marked 



As is evident from this experiment, the hemolytic immune body 

 is not affected by the formation of the specific precipitate. 



The alexin-fixing power of the precipitate is not specific as 

 regards alexin that is, it is able to absorb alexins other than those 

 of the species furnishing the precipitin. The fixation of guinea- 

 pig alexin, for example, is shown by: 



EXPERIMENT III. 

 Two tubes are prepared: 



Tube 1. Serum > ox, 55 degrees 0.025 c.c. (0.1 c.c. of a dilution of 1 to 4) 



Serum rabbit > ox, 55 degrees 2.00 c.c. 

 Tube 2. NaCl solution 0.1 c.c. 



Serum rabbit > ox, 55 degrees 2.00 c.c. 



