1910.] The Chemical Dynamics of Serum Reactions. 505 
Thus the value of « at the point of diversion in the divided experiment 
would be 
ae ae I 
“y= C tA Oo} 3 
in the simultaneous experiment 
i = Ae. 
The state of affairs is shown simply in the accompanying diagram :— 
Zz 
ie sinigy |. 
Let us suppose that the serum employed contained y of amboceptor and 
-%, of complement. In an ordinary simultaneous experiment, complete 
lysis would occur at the point a, the curve for complete lysis being the 
line a2. 
If, however, the experiment is performed in two stages, the initial action 
of amboceptor ¥ is to shift the line of complete lysis from % to %. Conse- 
quently, the line 2 will now be a line of partial lysis, the available quantity 
of complement x2 being insufficient to lyse the supersensitised cells. If x 
be increased to a, complete lysis will be attained. An advanced degree of 
this phenomenon is shown in the following experiment :—* 
| Inactive dog serum, JN B. 
1.€. Y. Consecutive reaction. Simultaneous reaction. 
z=0 z = complete lysis. 
9 bP) 99 
2) 2) 2) 
Or Or OU 
99 ” 
nearly complete lysis. 
0. 
2) | 
SCO0OOOF, 
oe COR on) 
2 =0'5c.c, guinea-pig serum. Cells = 1 c.c. of a 5-per-cent. suspension from guinea-pig. 
* Ehrlich, ‘Studies in Immunity,’ English edition, p. 211. 
