50 



PROPERTIES OF H^MOLYTIC SERA 



Series B. To each tube, 0-1 c.c. anti-S alone is added. 



All the tubes are placed in the incubator for an hour at 

 37 C. 



To the several tubes of both series alike are then added 

 increasing amounts of C, viz. 0-03, 0-04, 0-05 c.c., &c. Incu- 

 bation for another hour. To each tube the standard amount 

 of red corpuscles treated with IB is then added, and the 

 tubes are incubated for another hour. 



The results are shown in the following table : 



The effect of Cd in preventing the combination of C is 

 thus seen throughout. If we take the first tube, it is seen 

 that the previous addition of 0-1 c.c. Cd has kept out suffi- 

 cient C to produce lysis of 0-68 of the added corpuscles, L e. 

 about 0-02 c.c. C. 1 



1 It is shown below that excess of the homologous serum interferes with 

 the deviation of complement, and it might be suggested that the result 

 detailed is not due to complementoid, but to the serum receptors added 

 in the 0*1 c.c. heated serum. It is, however, to be noted that those serum 

 receptors also exist in the unheated serum, and that there are as many in 

 tube 9 of series B (0 16 c.c. of C) as in tube 4 of series A (0-06 c.c. of 

 C + 04 c.c. of Cd). The deviation effect should thus be the same in 

 both. But the actual amount of lysis is the same in both, though 9B 

 contains 04 c.c. more C than 4A. This appears only explicable on the 

 assumption that the Cd in 4A has prevented the C from combining. 



