60 PROPERTIES OF H^EMOLYTIC SERA 



4. Saturation with Guinea-pig's Cd. 

 Test with Rabbit's C. 



M.H.D. of guinea-pig's C = 0-07 c.c. 

 rabbit's C = 0-27 c.c. 



Three tubes taken containing 1 c.c. suspension of red cor- 

 puscles, treated with 6 IB. 



Lysis with 0-09 c.c. guinea-pig's C ; one hour in incubator. 

 Addition of 0-5 c.c., 0-75 c.c. and 1 c.c. of guinea-pig's Cd 

 to the several tubes ; two hours in incubator. 



Addition of 0-3 c.c. rabbit's C ; one hour for combination. 



Addition of the test amount of corpuscles treated with 

 IB. Result in the tube with 0-5 c.c. Cd, two-thirds of the 

 corpuscles underwent lysis ; in the other tubes with 0-75 c.c. 

 and 1 c.c. Cd, complete lysis took place. Complete satura- 

 tion had not occurred with 0-5 c.c. Cd, but with the other 

 amounts it had, so that at most about a tenth of a dose of 

 the rabbit's C was taken up. 



It is thus seen that it is possible to practically saturate 

 with complementoid the surplus R + IB molecules after 

 lysis. Other experiments have indicated that probably 

 a certain amount of complementoid is displaced by comple- 

 ment added afterwards. But the above results show that 

 when an excess of complementoid is used, the amount 

 displaced is reduced to a trifling amount. 



These results also confirm the result already obtained, 

 namely, that in the case under consideration the haptophore 

 groups of the rabbit's and guinea-pig's complements unite 

 with the same R + IB molecules (vide supw). 



CONCLUSIONS 



The following are the chief results obtained from the 

 experiments described. It is, of course, to be understood 



