E. A. Watson 
173 
Experiment for determining the Antibody content of Dourine Sera 
by the Complement Fixation Method. 
inactivated dourine serum 
c.c. 
No. 1 
Complement fixation reactions with dourine serum 
No. 2 No. 3 No. 4 No. 5 No. 6 
No. 7 
(0-2 
(undiluted, 
+ + + + 
+ + + + 
+ + + + 
+ + •+■ 4- 
4 4 4 4 
H—1—1—H 
+ + + + 
- Jo -15 
standard 
4 4 4 4 
+ + + + 
4 4 4 4 
+ + + + 
4 4 4 4 
4 4 4 4 
4 4 4 
(oi 
doses) 
+ + + + 
+ + + + 
+ + + + 
4-4 + 4 
4 4 4 4 
4 4 4 4 
4 4 
0-075 
(0-75 of 1 : 10) 
4 4 4 4 
+ + + + 
4 4 4 4 
4 4 4 4 
4 4 4 4 
4 4 4 4 
4 
0-05 
(0-5 „ „ ) 
4 4 4 4 
+ + + + 
+ + + + 
4 4 4 4 
+ + + + 
4 4 4 4 
- 
0-025 
(0-25 „ „ ) 
+ + + + 
+ + + + 
4- + + + 
4 4 4 4 
4 4 4 
+ + + + 
- 
0-01 
(0-1 „ „ ) 
4 4 4 4 
+ + + + 
+ + + + 
+ + + + 
4 4 
- 
- 
0-0075 (0-75 „ 1 : 100) 
+ + + + 
+ + + + 
+ + + + 
4 4 4 
4 
- 
- 
0-005 
(0-5 „ „ ) 
+ + + + 
++++ 
+ + 
4 
- 
- 
- 
0-0025 (0-25 „ „ ) 
+ 4 
+ + 
- 
- 
- 
- 
- 
0-001 
(0-1 „ „ ) 
+ 
- 
- 
- 
- 
- 
- 
0-2 (serum control, 
without antigen) 
- 
- 
- 
- 
- 
- 
- 
Indicated value of 
one antibody unit 
0-005 
0-005 
0-0075 
0-01 
0-05 
0-025 
0-2 
Number of antibody 
units in 0-2 e.c. of 
dourine serum — 
maximum dose. 
40 
40 
26 i 
20 
+ + + + means complete fixation of complement—absolutely no 
trace of haemolysis. Red cells more or less clumped. A very strong 
positive reaction. 
+ + + is also a strong positive reaction, with just a faint trace or 
tinge of haemolysis. 
+ + is a rather weak positive, indicating partial fixation—about 
one half the red cells haemolysed. 
+, a very weak or faint positive—slight fixation, with more than 
one half the red cells haemolysed. 
—, a negative reaction. Complete haemolysis of red cells. 
The smallest dose of serum which combines with antigen to cause 
complete fixation (+ + + +) indicates the value of one antibody unit, 
and from this may be calculated the number of units in the standard 
or maximum dose and the value of a dourine serum in antibody content. 
Such values are more relative than absolute, for the titre of a 
dourine serum may be somewhat higher or lower according to the amount 
of dourine antigen present and the fineness with which the haemolytic 
system has been adjusted—just as the titre of the haemolytic serum 
itself is correlative to the amount of complement and red cells (antigen). 
