TOXIC ACTION OF COMPLEMENTS 75 



the small circle indicating red corpuscles, the vertical dotted 

 line a period of incubation at 37 C., n indicating a definite 

 multiple of IB, and x varying amounts of C. 



IB Eabbit v. Guinea-pig. Combination of Guinea-pig's C. 

 Experiment XLII. 



2 doses of IB took up 0-08 c.c. guinea-pig's C. 



,, ,, 0-288 ,, ,, 



Dose of guinea-pig's C = about 0-3 c.c. 



Experiment XLIII. 



1 dose of IB took up 0-026 c.c. guinea-pig's C. 

 5 doses 0-114 



10 0-254 



Dose of C = 0-25 c.c. 



Experiment XLIV. 



1 dose of IB took up 0-014 c.c. guinea-pig's C. 

 14 doses 0-38 



Dose of C = 0-35 c.c. 



Experiment LXIX. 



1 dose of IB took up 0-04 c.c. guinea-pig's C. 

 5 doses 0-28 



. 10 0-48 



Dose of C = 0-4 c.c. 



From these results it is manifest that the large amount 

 of guinea-pig's complement necessary to produce lysis 

 combines completely with the guinea-pig's corpuscles 

 treated with the corresponding immune-body, there being, 

 up to a certain point, no complement left over to act on 

 the test corpuscles, and the large dose of immune -body 

 necessary is simply due to this amount being required to 

 bring the necessary complement into combination with the 

 corpuscles. The guinea-pig's complement has, therefore, a 

 weak toxic action on guinea-pig's corpuscles, about ten times 

 weaker than it has, for example, on ox's corpuscles. 



