TOXIC ACTION OF COMPLEMENTS 81 



as ' 10D. of IB.') leads to the taking up of more than a 

 haemolytic dose of rabbit's complement. This phenomenon 

 is, probably, related to the fact brought out by Morgenroth 

 and Sachs, 1 that the M.H.D. of complement sometimes 

 varies greatly, according to the amount of immune-body 

 used, and, conversely, the M.H.D. of immune-body may 

 vary greatly, according to the amount of complement. 

 The explanation of this is also outside the scope of the 

 present paper. 



(b) With Guinea-Pig's Complement 



The combination of guinea-pig's complement may be 

 exemplified by the following : 



Experiment LXII. 



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

 10 0-36 



Experiment LXIII. 



1 D of IB took up 0-012 c.c. guinea-pig's C. 

 10 0-27 



The indicator was ox's corpuscles treated with immune- 

 body. Here we have variations corresponding to those 

 noted above. 



We have also found that with this immune-body a small 

 quantity of guinea-pig's complement keeps out of combina- 

 tion a certain amount of rabbit's complement, and that 

 saturation with rabbit's complement implies practical 

 saturation for guinea-pig's complement also. A similar 

 statement applies to rabbit's complement keeping out 

 guinea-pig's complement. 



(c) With Ox's Complement 



Owing to the lack of anti-serum, we were unable to 

 study the combining relationships of ox's complement 

 through the medium of this immune-body. This defect, 

 however, cannot modify the main conclusions arrived at. 

 1 Morgenroth and Sachs, Berlin, klin. Woch., 1902, No. 35. 



MT7IR Q. 



