BIOLOGICAL THERAPEUTICS 



557 



6. The proper dosage is 0.2 milligram (gr. .003) of tuberculin, 

 which is contained in two tablets. The tuberculin is non-irritating to the 

 normal eye and it must be remembered that irritants of varied types may 

 produce eye discharges. Hence only normal eyes should be selected for 

 testing. 



7. The so-called sympathetic reaction is not confirmative of tuber- 

 culosis, and animals exhibiting discharges from both eyes should be 

 classed as suspicious and be retested when normal conditions exist. 



8. Hyperemia is not invariably present. When limited to the 

 treated eye it may be regarded as confirmative of a reaction. It appears 

 more uniformly in sensitized eyes, also in the treated eye of an animal 



that has reacted to subcu- 



taneous tuberculin within a 

 short time. 



9. The best results are 

 obtained from this test 

 when one sensitizing tablet 

 is used two or three days 

 prior to the application of 

 the regular ophthalmic test. 

 This method should be fol- 

 lowed wherever practicable. 



The Combined Applica- 

 tion of the Three 



Tests. 

 Recent experiences of 

 the bureau indicate that in 

 badly diseased herds, or in 

 herds which have been in- 

 jected frequently with tu- 

 berculin by the subcutane- 

 ous method, it is advisable 

 to apply the ophthalmic 

 and possibly the intrader- 

 mal tests. Whenever all 

 these tests are employed, 

 the intradermal injection should be made first, and at the same time one 

 ophthalmic disk should be inserted as a sensitizing agent for the regu- 

 lar ophthalmic test. 



Observations should be made following the use of the sensitizing 

 tablet, as frequently typical reactions occur from the use of one tablet. 



Intradermal observations should be made on the forty-eighth, sev- 

 enty-second, and ninety-sixth hours. Two ophthalmic disks should be 

 used the second or third day, and at the same time the regular inj ection 

 by the subcutaneous method can be made. 



It has been observed that the combined use of the three tests detects 



additional reactors which might have escaped one of the tests alone. 



Whenever this method is followed a detailed report covering the work 



should be submitted to the bureau. ,,. ^^ 



DigitizeaDy Microsoft® 



An Averagre Positive Reaction to the Ophthalmic 

 Test for Tuberculosis, Showing a Dis- 

 tinct Purulent Discharge 



