OPHTHALMIC MALLEIN FOE THE DIAGNOSIS OF GLANDERS. 9 



times longer. The reaction consists of a purulent discharge from 

 the conjunctival sac which is typical, as well as swelling and gluing 

 of the eyelids. It is advisable to examine the tested animals in a 

 good light from 12 to 24 hours after the application of the test. 

 Varying degrees of reactions are illustrated in Plate I, figures 1 to 4. 



A suppurative discharge of varying quantities is considered a 

 positive reaction. The conjunctiva and the eyeball should also be 

 included in the examination after examining the discharge. A 

 pseudo-reaction can be produced by artificial or accidental irrita- 

 tion of the eye. On the other hand the purulent discharge may 

 have been removed (either by the stable attendant or by the animals 

 licking each other, etc.), and the positive result thus obliterated. 

 In such cases dried pus may be frequently found on the parts around 

 the eye. 



Generally the positive ophthalmic reactions are not accompanied 

 by fever or systemic disturbances. Occasionally, however, affected 

 horses are hypersensitive to such a degree that even the few drops 

 of mallein placed in the eye may enter the circulation and produce 

 fever. Therefore it is advisable, when possible, to accompany the 

 ophthalmic reaction with temperature readings. For this purpose 

 the temperature should be taken twice, the first time when the eye 

 test is being made and the second time when it is judged. In a 

 doubtful eye reaction, where there is an increased temperature of 

 1| degrees F., the test should be considered positive if the animal 

 had a normal temperature at the time the test was made. As stated 

 before, it should be remembered that the intensity of the reaction 

 has no relation to the extent of the disease in the animal tested. 



In the absence of any secretion the test should be considered nega- 

 tive. When there is a mucous secretion or lacrimation during the 

 period of reaction the test must be considered as atypical, and in 

 such cases it may be repeated the same day, when, as a rule, the 

 results are more confirming. 



The application of the ophthalmic test should not be repeated 

 more than three times on the same animal within three months, as 

 experiments show that the reaction after the third application within 

 this short period usually loses its intensity in positive cases, and on 

 subsequent tests may be entirely absent. In cases where the results 

 of the second test immediately following the first test are atypical, 

 the blood of such animal may be drawn and forwarded to a labora- 

 tory for the serum diagnosis. From experience gained with the eye 

 test such a procedure would become necessary only in a compara- 

 tively few cases. In the control of glanders, animals may be retested 

 every six months with satisfactory results. 



