PROPERTIES OF COMPLEMENTOIDS 59 



Examples 1 and 2. Saturation with Rabbit's Cd. 



Test with Rabbit's and Guinea-pig's C. 

 M.H.D. of IB = 0-002 c.c. 



guinea-pig's C = 0-045 c.c. 



rabbit's C = 0-11 c.c. 



(0-5 c.c. of suspension of red corpuscles is used, so that the 

 doses will be half the amount.) 



5 D of IB added to four tubes, A, B, C, D. 

 Lysis in all with 0-07 c.c. rabbit's C. 

 0-6 c.c. rabbit's Cd added to each tube ; two hours at 

 37 C., then add 



A. B. C. D. 



0-065 c.c. 0-09 c.c. 0-03 c.c. 0-05 c.c. 



Rabbit's C. Guinea-pig's C. 



One hour in incubator. 



Add to each 0-5 c.c. of suspension of red corpuscles treated 

 with IB. 



The result is that complete lysis of all the added corpuscles 

 occurs. This shows that at most not more than a fifth of 

 a M.H.D. of rabbit's C and not more than a third of a M.H.D. 

 of guinea-pig's C has been taken up. 



3. Saturation with Guinea-pig's Cd. 

 Test with Guinea-pig's C. 



M.H.D. of guinea-pig's C = 0-04 c.c. (at beginning of 

 experiment), 5 D of IB added to 1 c.c. corpuscles, lysis with 

 C and addition of 0-5 c.c. of Cd, two hours at 37 C. ; 0-06 c.c. 

 of C added, one hour at 37 C. ; red corpuscles treated with 

 IB added, one hour at 37 C. Result, 0-8 of the corpuscles 

 underwent lysis, but in a control with 0-06 c.c. of C alone 

 0- 1 remained undissolved. Here, accordingly, not more than 

 about a tenth of a dose of C subsequently added entered 

 into combination with the R + IB molecules. 



