BIOLOGICAL PRODUCTS (VETERINARY). 
679 
Reaction sometimes fails in advanced cases of the diseases, 
but in such cases the symptoms are usually diagnostic. If a pri¬ 
mary test leaves the matter in doubt, the animal should be re¬ 
tested in a month or two. 
Agglutination Test Fluid .—The agglutination test for the 
diagnosis of glanders has been used for several years and with 
reasonably good results. This test is based on the fact, as previ¬ 
ously mentioned, that in the case of glanders as well as some 
other diseases, there is developed in the blood, antibodies known 
as agglutinins, which have the power of clumping and precipitat¬ 
ing the specific bacteria of the disease. The test fluid or sus¬ 
pension containing the glanders bacteria is prepared by inocu¬ 
lating acid glycerin agar with highly virulent cultures of the 
glanders organisms. After 24 or 48 hours’ incubation the 
resultant growth is removed from the media by adding a quan¬ 
tity of normal salt solution. The suspension is heated to destroy 
the organisms and then diluted to the desired density. 
In applying the test, serum from the suspected case is added 
to the test fluid, several dilutions being made. Usually the dilu¬ 
tions prepared are 1 part of serum to 800 of test fluid, 1-1200, 
1-1500 and 1-1800. The reason for making such high dilu¬ 
tions is that normal serum frequently contains a sufficient 
amount of agglutinins to cause the characteristic reaction in dilu¬ 
tions as high as 1-500 or 800, so that in order to make the test 
or diagnostic value much higher dilutions must be employed. 
After the dilutions are prepared they are incubated for 24 or 45 
hours. A positive reaction consists of a clumping and precipi¬ 
tating of the organisms in the test fluid, so that the fluid will 
have lost its turbidity and be perfectly clear. The clumped or¬ 
ganism will have settled in a mass at the bottom of the test tube 
or container. A positive reaction in dilutions of 1-1200 or 
higher is indicative of glanders. 
This method is an accurate means of diagnosis if proper care 
is used in making the test. It is of great value in conjunction 
with the mallein test, especially in those cases which are con¬ 
sidered doubtful. It is important that an active suspension be 
employed for the test in order to obtain reliable results. 
