178 
Dourine 
Second method of procedure—-for daily routine testing or when 
50, 100, or more tests are to he made. 
This is only a slight modification of the first method of procedure 
to allow of more rapid and less laborious work in testing large numbers 
of suspected sera. 
Two test series are made, the first series, in which only one tube 
for each serum is used (instead of four tubes as before), containing the 
maximum dose, 0-2 c.c., and antigen, eliminating all negative sera and 
at the same time indicating the positive sera. These latter are again 
tested on the following day, using the four tubes—the three standard 
doses of serum and serum control—as in procedure No. 1, including 
them with the next lot of sera to undergo the first test in which the 
single tube is used. 
If a negative serum does not give a fixation reaction with 0-2 c.c. 
serum it certainly will not with the lesser doses, and as a serum control 
is only needed in the case of a serum which fixes complement, the 
single tube is obviously all that is required to determine a negative 
serum. Further, the sera with which complement fixation takes place 
in the one series serve as additional controls when included with and 
fnlly tested out in the second series—one day’s work thus checking 
the other, continuously. 
In routine testing at this laboratory, when large numbers of sera 
are being dealt with, it is the practice to make a repeat test with each 
serum negative at the first test and to arrange the work and the different 
series so that each day’s tests include: (a) a series not before tested 
(one tube for each serum); ( b ) the sera tested the day before with 
negative result (one tube for each serum); (c) the sera tested the day 
before with fixation reactions (four tubes for each serum); and, in 
addition, the usual series of known positive dourine sera, negative 
controls and reagent controls. 
All suspected sera are thus tested twice over so that if any error or 
omission in the technique has been made it will surely be indicated. 
Interpretation of the reaction. Fixation of the complement, not in 
itself visible in the test tube, is indicated by the prevention of haemolysis 
of the red cells and constitutes a positive reaction, on which a diagnosis 
of dourine is given. 
When no complement is fixed the red cells are completely haemolysed 
and the reaction is then said to be negative. 
