268 TUBERCULOSIS. 



are of any significance. In the United States the results differ 

 so widely that figures have, as yet, little value. Sometimes every 

 animal in a herd is found to be tuberculous, while other whole 

 herds are entirely exempt. In the eastern States the percent- 

 age is large, and in some localities it appears to approach the 

 figures given for Denmark. When the numbers of infected animals 

 in a herd range from o to 100 per cent, it is evident that no resulting 

 average would be of any significance. 



Increase of the Disease. Is bovine tuberculosis on the 

 increase ? Statistics are so uncertain as to make any conclusion 

 difficult. Certainly we hear much more of the disease than we 

 did a few years ago, and the percentages reported to-day are much 

 higher. The knowledge of the disease is, however, of very recent 

 date, and the increasing interest in the subject has caused a more 

 and more careful inspection of slaughtered animals, which has 

 resulted in a constant increase in the number of reported cases. 

 Even in the same slaughter houses and under the same management, 

 the percentage of tuberculous animals reported has been increasing 

 year by year in such a way as to seem to indicate an alarming 

 increase in the last fifteen years. But a considerable part of this 

 increase is clearly due to increased experience and carefulness in 

 inspection. To what extent this factor explains it, and to what 

 extent there is an actual increase in the disease, no one can pretend 

 to say. It is, therefore, impossible to state whether bovine tubercu- 

 losis is rapidly or slowly increasing or remaining stationary. 

 But taking all facts together, the practical uniformity with which 

 the percentage of reported cases has increased in the last years, 

 has led to the general belief that the disease is actually and some- 

 what rapidly increasing among our herds. 



But although no definite statistics can be given, either as to 

 the prevalence of the disease or its increase, bovine tuberculosis 

 is abundant enough. It presents a very serious problem to the 

 farmer. Entirely independent of the question of its relation to 

 human tuberculosis, the disease, as it exists among cattle, is a 

 menace to the dairy industry. The amount of financial injury 

 that it does to the farmer each year is very great far in advance of 



