Tuberculosis in Live Stock 
17 
Fig. 9.—Part of a herd of 69 cattle, 30 per cent tuberculous in 1917,5 per cent tuberculous in 1918, 100 per 
cent free from tuberculosis in 1919. The herd is now accredited. 
disease upon the application of the ophthalmic test. The ophthal- 
mic tuberculin is placed in one eye and the other eye is used as a 
check. A reaction is indicated by a characteristic discharge from 
Fig. 10.—How a herd may become reinfected with tuberculosis. This herd was free from tuberculosis for 
a number of years. During 1917, 4 cattle were purchased in another State and placed in the herd with¬ 
out proper tuberculin test. When official test was made, December, 1917,5 reactors were found. Three 
of the reactors were slaughtered and 2 kept in the herd. At the next test, January, 1919, 11 reactors 
and 2 suspects were in the herd of 28 cattle. 
