1904.] On Chemical Combination and Toxic Action, etc. 305 



Experiment LXXIV. 1 D of IB took up 004 c.c. of ox's C. 



0-042 







The indicator was guinea-pig's corpuscles treated with immune-body, 

 for which the dose of ox's complement was 0*02 c.c. 



//. Immune-body to Rabbit's Corpuscles (obtained by injecting the Guinea- 



(a) With Rabbit's Complement, 



This case is in many ways analogous to that of the immune-body to 

 guinea-pig's corpuscles along with guinea-pig's complement. In both 

 cases the hsemolytic dose of immune-body is ten times greater when the 

 complement of the animal whose corpuscles are being tested is used, 

 than when the complement of the other animal is used. This will be 

 seen from the table. In this case, also, the dose of rabbit's comple- 

 ment is high, just as in the previous case the dose of guinea-pig's 

 complement was. How much rabbit's complement is taken up when 

 multiple doses of immune-body are used? The scheme of experi- 



ment is : 



Eabbit's Q + n IB + x rabbit's C | + Ox's Q + IB. 

 The following are some of the results : 



Experiment LXIL 1 D of IB takes up 0-14 c.c. rabbit's C. 

 10 M6 



LXIIL 1 D of IB takes up 0'22 c.c. rabbit's C. 

 10 1*12 



LXVL 1 D of IB takes up 0-086 c.c. rabbit's C. 

 5 0-55 



10 0-9 



Dose of rabbit's C with rabbit's corpuscles = 0'6 c.c. " 1 D " = M.H.D, 

 of IB along with guinea-pig's C. " 10 D " = M.H.D. with rabbit's C 

 (vide tables). 



It will be seen that there is no lack of combining-power on the part 

 of rabbit's complement, and that the amount increases with the amount 

 of immune-body, though considerable deviations from exact arithmetical 

 proportions are met with. Sometimes more, proportionally, is taken up 

 by 10 hsemolytic doses than by 1 hsemolytic dose, sometimes less; we 

 have met with the former phenomenon in several other experiments 

 than that quoted, and are not able to give at present an explanation of 

 it. Another point is that the hsemolytic dose of immune- body 

 (expressed as "10 D. of IB.") leads to the taking up of more than a 



