IMMUNIZATION TESTS WITH GLANDERS VACCINE. 7 



All animals were subjected periodically to clinical examinations 

 and only four of the vaccinated horses developed signs of the disease 

 up to the conclusion of this experiment, although some of them were 

 exposed since May 16. Horse No. 99, which received 4 immunizing 

 injections and was exposed to a discharging case of glanders in the 

 stable, died 15 days after the exposure from acute broncho-pneu- 

 monia malleosa. 



In order to determine whether any of the vaccinated horses were 

 infected with the latent form of the disease, all were subjected July 

 23 to the ophthalmic test. This gave surprising results. Two of 

 the vaccinated animals gave a marked reaction (P+ + +)• A 

 similar reaction was also obtained in the affected horses used for 

 exposure, while of the two check animals which were not vaccinated 

 but had been exposed to a similar extent as the vaccinated animals, 

 only one responded to the test; the other check animal failed to give 

 any reaction. One month later all horses in the experiment were 

 again subjected to the ophthalmic test. The results were the same 

 as on the previous test, but it was noted that the intensity of the 

 reaction was not as pronounced as in the first test. The inflammation 

 and amount of purulent discharge were somewhat less than in the 

 previous test. This observation coincides with that of Meyer, who 

 states that after several eye tests in positive cases of glanders the 

 degree of the reaction becomes less distinct. 



The detailed account of the results of the immunizing tests in 

 horses is given in Table 2. 



