CHAPTER XI. 

 TUBERCULOSIS. 



This disease is known by many names, consumption, 

 -or phthisis in man, grapes or pearl disease in cattle ; it is 

 also often called the great "white plague." It is charac- 

 terised by the formation in the body of nodules or tu- 

 bercles, hence the name tuberculosis. It is the most im- 

 portant disease of man, as well of domestic animals. It 

 causes one seventh of all deaths of human beings, and a 

 much larger proportion of the deaths of people between 

 the ages of twenty and forty years. 



Animals affected. All of the domestic animals may 

 be affected, but it is most prevalent amongst cattle, hogs, 

 and hens; much less so amongst horses, sheep, dogs and 

 -cats. From an economic or a hygienic standpoint, con- 

 sideration need be given to the disease only as it appears 

 in cattle, hogs, and fowls. 



Geographical distribution of tuberculosis. The dis- 

 ease is world- wide in the case of man and almost equally 

 so in cattle. All the important special breeds of cattle 

 have originated in Northwestern Europe ; from here they 

 have been carried to all parts of the world, and they have 

 carried with them this disease. The- native cattle of most 

 countries were free from tuberculosis until the improved 

 breeds were introduced. The islands of Jersey and 

 Guernsey are free from bovine tuberculosis, and are kept 

 free because no live cattle are imported. 



