70 
Journal of Agricultural Research 
Vol. XI, No. 3 
This titration indicates the largest amount of antigen which does not 
interfere with conglutination. After this preliminary titration the 
antigen is titrated against known positive and negative glanders serum, 
with varying amounts of antigen, the investigator being guided in these 
amounts by the results of the preliminary titration, so as not to use 
quantities so large that interference with conglutination occurs (Table IV). 
Table; IV .—Titration of antigen against known positive and negative glanders serum 
Tube No. 
Glanders serum.® 
Antigen.b 
Comple¬ 
ment. c 
Inacti¬ 
vated cow 
serum.d 
Sheep- 
blood cor¬ 
puscles. ® 
Result./ 
Positive. 
Negative. 
C. c. 
C. c. 
C. c. 
C.c . 
C. c. 
C. s. 
T. 
O. 1 
0. 03 
0 . I 
0. 8 
0. 1 
__ 
2. 
. 1 
. OK 
. I 
.8 
. 1 
_ 
2 . 
, 1 
• w j 
.08 
. I 
.8 
. 1 
_ 
O . 
A . 
, 1 
. 1 
. I 
.8 
. 1 
_ 
.. 
5 . 
. I 
•15 
. I 
.8 
. 1 
- 
6. 
. 1 
. 2 
. I 
.8 
. 1 
— 
, 1 
. I 
.8 
. 1 
+ 
1. 
. I 
. I 
.8 
. 1 
+ 
2. 
. 1 
.08 
. I 
.8 
. 1 
+ 
2 . 
. 1 
. I 
. I 
.8 
. 1 
+ 
. 1 
• I? 
. I 
.8 
. 1 
+ 
t?.. 
. 1 
. 2 
. I 
.8 
. 1 
± 
J 
6 . 
. 1 
. * 
. I 
.8 
. 1 
7. 
. 1 
0 
, I 
.8 
. 1 
+ 
/. 
8 . 
, I 
.8 
. 1 
+ 
a Known positive and negative glanders serums, 
b Glanders-bacilli extract. 
c Fresh normal horse serum. 
d Inactive cow serum diluted so that each 0.8 c. c. contains 0.02 c. c. of cow serum. 
« Five per cent suspension of sheep-blood cells. 
/ += conglutination; ±=partial conglutination; —=no conglutination. 
Tube 7 is a control on the positive and negative serum, while tube 8 
controls the conglutination system. The antigen is used as strong as 
possible; that is, the largest amount inhibiting conglutination in the 
positive case is used, provided that twice this amount does not interfere 
with conglutination in the negative case. In Table IV the titer of 
the antigen would be represented by 0.08 c. c. The antigen should be 
titrated each time a test is made. 
INACTIVATION OF TEST SERUM 
The serum to be tested is inactivated at 58° C. for half an hour, and 
should be clear and in good condition. Occasionally, however, in the 
quantities used in the test (0.05 and 0.1 c. c.) the serum controls will 
show an inhibition of conglutination. This occurs with serum that is 
heavily carbolized, decomposed, or with clear serum that has been kept 
at room temperature for a considerable period. 
In a number of instances this serum can be utilized by titrating 
the serum against the conglutination system by using in the test 
proper the largest amount of serum not interfering with conglutination 
(Table V.). 
