230 



COLLECTED STUDIES IN IMMUNITY. 



dominant for case B but non-dominant for case A. It was next 

 necessary to determine whether or not in case A the absorption of 

 the non-dominant complement ft is dependent on the binding of the 

 dominant complement a. Owing to the peculiar nature of the anti- 

 complement it is possible to prevent the binding of complement a 

 for case A, whereas the binding of complement ft for case B is 

 not affected. On the addition of 0.4 cc. of the anticomplement 

 serum the amount of complement necessary for complete solution 

 increases from 0.0075 cc. to 0.2 cc., i.e. 26 times, whereas no change 

 occurs for case B, 0.005 of the guinea-pig serum still causing com- 

 plete solution. 



If, therefore, the binding of the complement ft by ox blood-cells 

 laden with amboceptor A is dependent on the binding of the domi- 

 nant, complement a, it must be possible by the addition of the fluid 

 containing the anticomplement to prevent this binding. The ex- 

 periment is made 'as follows : 



First, 0.4 cc. anticomplement serum is mixed with varying 

 amounts of guinea-pig serum. After this mixture has remained at 

 room temperature for half an hour the ox blood-cells laden with 

 amboceptor are added and the whole kept in the thermostat for 

 1J hours, when the undissolved blood-cells are centrifuged off. The 

 decanted fluid is mixed sheep blood-cells loaded with their ambo- 

 ceptor. The result shows that in this case a decrease of complement 

 b for B has not occurred, for the tube containing 0.005 guinea-pig 

 serum shows complete solution. The following table will make the 

 results plain: 



COMPLETE SOLVENT AMOUNTS OF GUINEA-PIG SERUM. 



By means of this experiment, therefore, it has been proved that 

 in this case binding of the non-dominant complement ensues only after 

 the corresponding complementophile group of immune body A has an- 



