IMMUNIZATION TESTS WITH GLANDERS VACCINE. 13 



from the sanitarian's standpoint this would be of theoretical impor- 

 tance only, since even if such should be the case an immunity of from 

 two to four months could not be considered sufficient for practical 

 vaccination purposes. Furthermore, it should be remembered that 

 some of these horses developed a latent form of the disease in 

 less than three months from the last vaccination during the period in 

 which the blood still contained the so-called immune bodies. 



CONCLUSIONS. 



The results obtained by these investigations appear to be sufficient 

 to demonstrate the unsatisfactory results of this method of immuni- 

 zation. Of the 13 immunized animals, 9 contracted the disease 

 from natural exposure, which is a large proportion when it is consid- 

 ered that all animals were aged and kept most of the time during 

 the exposure out of doors. Of the 4 remaining immunized horses, 

 1 died of impaction after the second vaccination, while the other 

 3 animals were killed August 20, 1913, in order to ascertain by post 

 mortem examination the possibility of glanders existing in these 

 animals which had given positive serum reaction, but which had 

 returned to normal. In artificial infections of the vaccinated ani- 

 mals they showed no resistance whatsoever, as both vaccinated 

 horses promptly developed an acute form of the disease from touch- 

 ing the Schneiderian membrane with a platinum loop which had 

 been touched .to a growth of glanders bacilli. For the present", 

 therefore, it seems advisable to abstain from immunizing horses 

 by this method, as a practice of this kind may' do more harm than 

 good. Owners having horses which are supposedly immunized 

 would naturally become careless, thinking their animals were resistant 

 to the disease, and thus even a better opportunity would be offered 

 for the propagation of the disease than if the horses were not vac- 

 cinated. Furthermore, the fact that the blood of vaccinated ani- 

 mals can not be utilized for serum tests for two or three months 

 after the injections is also a great disadvantage in the eradication 

 of the disease. 



As a result of this preliminary work it appears that the control 

 and eradication of glanders must still be dependent upon the con- 

 centration of our efforts in eliminating infected horses and the adop- 

 tion of proper precautions against the introduction of infected ani- 

 mals into stables free from the disease. The results achieved in 

 Germany, Austria, and Canada by these methods have proved very 

 encouraging, and no doubt if executed in the same spirit in this 

 country a marked reduction in the cases of glanders would result. 



