128 ANNUAL REPORT OP THE Off. Doc. 



cattle, the individual tubercular cow is not likely to spread tuber- 

 culosis rapidly or widely. Wlieu several animals have become in- 

 fected from this individual and are carried to other herds, the 

 disease will spread as many times faster than at first as there are 

 more animals spreading- it. As the number of animals distributing 

 disease increases, the ratio of its spread increases until, at length 

 when one hundred animals have been infected and are distributing 

 the disease it goes at one hundred times the original rate of pro- 

 gress. 



Notwithstanding the very wide distribution of tuberculosis in 

 Pennsylvania, which has been so great as to convince many stock- 

 men that little could be done in the way of repression and that they 

 had come to look upon tuberculosis as a necessary evil and to figure 

 the losses caused hy it annually as a part of the necessary expenses 

 of keeping cattle, it has been possible, during the comparatively 

 short existence of the State Live Stock Sanitary Board, to bring 

 about a very great diminution in the prevalence of this disease 

 and in the losses from it. The results so far attained encourage 

 the belief that it is not only possible but entirely probable, that 

 tuberculosis may be reduced in the course of a series of years and 

 abolished to a point where it may readily be kept in control and 

 where it will cease to cause losses of material importance. Tuber- 

 culosis has already been eradicated from a large number of indi- 

 vidual herds and from many large groups of herds. In some in- 

 stances the disease has been practically eradicated from entire 

 counties. What can be accomplished, and what has been accom- 

 plished, in relation to individual herds and groups of herds in large 

 districts, can be accomplished in relation to other herds and groups 

 of herds and in relation to the cattle of the entire State. The task, 

 however, is a large one. The size of Pennsylvania and the great 

 number of herds in the State render complete inspection of all of 

 the herds so expensive an undertaking as to make it impossible of 

 accomplishment under existing conditions. Fortunately, however, 

 Pennsylvania has a body of veterinarians of unusual intelligence 

 and skill. The results that have been accomplished by the State 

 Live Stock Sanitary Board are due largely to the enthusiastic and 

 efficient co-operation of the veterinarians. Moreover, and the im- 

 portance of this item cannot be exaggerated, the Live Stock Sani- 

 tary Board has, at every point, had the most friendly co-operation 

 of the owners of cattle. These facts have made it possible to ac- 

 complish a great deal more with the funds at the disposal of the 

 State Live Stock Sanitary Board than could possibly have been ac- 

 complished with several times as much money if, as in some states, 

 the veterinarians and live stock owners were not in sympathy with 

 and were not working in co-operation with the authorities having 

 charge of the control of the diseases of animals. 



