502 Captain A. G. McKendrick. [ Nov. 30, 
GG; 
Series 2.—Serum mixture (A, B, C, D, or E) ............ 0°30 
0°85-per-cent. NaCl solution........4....-2-tu-.- 1:45 
Washed horse-cellisay. 4.2.4... oeccuen eee eee 0:05 
Potals See ge aa eee 2:00 
ze. in this series amboceptor = 25 per cent. 
The tubes were incubated at 37 C. for two hours, and kept on ice over- 
night. They were then estimated for lysis by colorimetry. 
The results are as follows (wide Chart 3):— 
| 
Observed lysis. | Zz. x used. a calculated. 
| B | 52-0 0 “86 87 5 36 “87 
geeeue EO C 32-0 0°53. 25-0 2412 
fea mac £50) 14°6 0 243 12°5 11 608 
E 6°8 0:113 6 25 5 54 
es 80 °4 1°34 25-0 25 16 
| 8 61-0 1-016 18 “75 19 284 
| Series 2. y=25 ...4 OC 39 -2 0 °653 12 °5 ET ILy/ 
| D 19:0 0 °316 6 25 7-02 
_ E| 9°8 0-163 3125 3°83 
| 
Constants c = 10, z = 0°83 for 50 per cent. lysis. 
The constants were obtained as follows :— 
The observed results having been charted it was observed that in the 
curve for (y = 25) there was a point of inflexion whose co-ordinates were 
approximately (Lysis = 50 per cent.) (2 = 15°5). 
By equation (11) = ae9, wos we = Set 
By equation (12) Cee NUS ee = Oil Oi. 
Substituting this value in (11), | 
C= 83/0707 = 1045. 
These approximations were subsequently modified to c = 10 and z = 0°88 
for 50 per cent. lysis. 
Chart 3 shows more remarkably than the tabulated results do, how 
complete is the accordance between the theoretical and the observed forms 
of curve. (In the lowest curve in Chart 3, y = 50.) 
The / form, with its point of flexion, is shown for the value y = 25, and 
the preliminary concavity for the higher value y= 50. An experimental 
point of note is that for observed results to agree with the equation of 
equilibrium, it is absolutely necessary that the reaction should be allowed to 
