136 



THE BACTEKIOPHAGE 



Moreover, the antigen by itself fixed complement. 



Experiment XLVII. Antigen : culture of anti-Shiga bacteriophage con- 

 taining 100,000,000 ultramicrobes per cubic centimeter. 



Antibody: antibacteriophage-Shiga serum. 



Positive fixation was secured with mixtures containing the antigen in 

 1 cc. amounts and the serum in 0. 2 and 0.1 cc. quantities. 



The antigen by itself did not fix complement. 



Experiment XLVIII. Antigen: B. dysenteriae Shiga. 



Antibody: antibacteriophage-Shiga serum. 



Fixation of complement occurred. 



Experiment XLIX. Antigen: culture of the anti-Shiga bacteriophage. 



Antibody: an antidysentery serum. 



Complement is fixed. 



Experiment L. Antigen: culture of the anti-Shiga bacteriophage. 



Antibody: antibacteriophage-Shiga serum. 



The antigen, antibody, and complement are incubated together for 1 

 hour at 37C., and then the hemolytic system is added. 



The following protocol shows the results. 



Experiment LI. Antibody: antibacteriophage-Shiga serum. 

 Antigens: Four different antigens are employed, as follows: 



I. Anti-Shiga bacteriophage, 1,500,000,000 ultramicrobes per cubic 



centimeter. 



II. Anti-barbone bacteriophage, 250,000,000 ultramicrobes per cubic 

 centimeter. 



III. Anti-plague bacteriophage, a strain derived from the rat, 



450,000,000 ultramicrobes per cubic centimeter. 



IV. Anti-plague bacteriophage, a strain derived from a case of plague 



in man, 700,000,000 ultramicrobes per cubic centimeter. 

 The results secured with these four different antigens are shown in the 

 following table. 



