120 ILLINOIS STATE DAIRYMEN'S ASSOCIATION 



used in connection with either of the previously described 

 methods. Sometimes a tuberculous animal that fails to re- 

 act to those tests shows evidence of the disease upon the 

 application of the ophthalmic test. The ophthalmic tuber- 

 culin is placed in one eye and the other eye is used as a 

 check. A reaction is indicated by a characteristic discharge 

 from the eye receiving the treatment, which may occur in 

 from 3 to 10 hours after the application or even later. 

 Some swelling and inflammation of the eye and lids are of- 

 ten noted. 



Reliability of the Principal Tuberculin Tests. 



The subcutaneous test is made by injecting, under the 

 skin, a small quantity of tuberculin. Carefully and consci- 

 entiously applied, with good judgment exercised in both its 

 administration and interpretation, it is wholly effective,. 



The intradermic test is especially suitable for range 

 cattle or animals whose movements are difficult to control, 

 and in area work. In this test the tuberculin is injected 

 between the layers of the skin. 



The ophthalmic test, or so-called "eye test," is not at 

 present accepted for testing cattle for inter-state shipment, 

 though it has value as a check test and is recognized for 

 that purpose. It is applied by placing the ophthalmic tu- 

 berculin in one eye, using the other as a check. The oph- 

 thalmic test has given best results under farm conditions 

 or in other cases where the eyes are normal. For testing 

 cattle in transit or in the stockyard the test is less depend- 

 able, owing to the fact that the eyes may be abnormal as 

 the result of irritation or injury from dust, cinders, or other 

 results of transit. In all cases the tests, used either alone 

 or in combination, should be applied by capable persons 

 familiar with tuberculin testing. 



Post-Mortem Appearances. 



Animals affected with tuberculosis may show the ef- 

 fects of the disease in almost any part of the body. In ad- 

 vanced cases the lesions are easily found, but when the dis- 



