354 ANNUAL REPORTS OF DEPARTMENT OF AGRICULTURE. 



The following is a summary of all tuberculin tests applied in con- 

 nection with bovine tuberculosis in the District of Columbia during 

 the fiscal year : 



Total number of cattle tested 1,390 



Number passed 1, 358 



Number reacting and suspected 32 



Percentage of reactors and suspects 2.30 



Reactions confirmed by post-mortem examination per cent 100.00 



ACCUBACY OF THE rtTBERCULIN TEST. 



The accuracy of the tuberculin test is shown by the results of post- 

 mortem examinations covering a period of five years, extending from 

 1907, during which time tests were applied under varying weather 

 conditions by a number of different inspectors, under the supervision 

 of the Quarantine Division, working in Virginia, Maryland, and the 

 District of Columbia. Out of 1,900 reacting cattle slaughtered and 

 examined post-mortem, the lesions of tuberculosis were demonstrated 

 in all but 41, thus confirming the tuberculin test in 97.85 per cent of 

 the cases. 



COOPEEATIVE TXIBERCULOSIS INVESTIGATIONS IN UTAH. 



Tlie cooperative tuberculosis investigations in Utah were inaugu- 

 rated August 29, 1909. As a result of the first investigations it was 

 found that in the majority of instances the infection of native cattle 

 could be traced to eastern cattle which had been brought into the 

 State for the purpose of improving the quality of its breeding stock. 

 The infection was found to be most prevalent among dairies supply- 

 ing large cities with milk, while in other sections the percentage of 

 tuberculosis was much smaller. 



The results obtained by the tuberculin test applied from October 

 29, 1909, to the end of that fiscal year, June 30, 1910, showed the 

 presence of 5.3 per cent of tuberculosis among 5,989 cattle tested. 

 During the past year tests were applied to 6,G76 cattle, of which 72 

 reacted to the test, reducing the percentage of tuberculosis to 1.1 

 per cent. 



The greatest amount of tuberculosis was found among the dairies 

 supplying milk to Salt Lake City, and as a result of the first test, 

 which was applied to 1,271 cattle found in these dairies, 9.44 per cent 

 were classified as tuberculous. On the last retest, at which time the 

 55 dairies supplying Salt Lake City contained 1,304 cattle, the per- 

 centage of tuberculosis showed a reduction to 1.99 per cent. 



COOPERATIVE TUBERCULOSIS INVESTIGATIONS IN INDIANA AND OHIO. 



During the past year cooperative tuberculosis investigations have 

 been conducted from the Cincinnati (Ohio) station of the bureau, 

 in cooperation with the States of Indiana and Ohio, with the Cin- 

 cinnati Medical Society Milk Commission in testing herds for the 

 producton of certified milk, and with the director of public safety of 

 Cincinnati, under whose control are the herds which supply milk 

 to the city institutions. The work has not been in progress long 

 enough to include a large number of animals, the total number of 

 tests being 3,074. It will be seen, however, from the following table, 

 which sunmiarizes the work already done, that the percentage of 



