Tuberculosis. 447 



Petersburg it is as prevalent as in the large cities of Central 

 Europe. Elevated and dry climates have often been found to be 

 free from the affection, yet it prevails inside the double windows 

 of houses in the higher Alps, and has, within a generation estab- 

 lished a notorious prevalence in Minnesota, Dakota and westward, 

 as it has in Australia, mainly owing to the advent of consump- 

 tives who sought for health in the dry atmosphere. The hills 

 and dry tablelands in North and South America, Africa and Asia 

 "which have acquired a reputation for salubrity, owe this largely 

 to the sparse population and the absence of facilities for infection. 

 In South Africa, in spite of the dry and genial climate, the disease 

 is constantly encreasing in the human (housed) population. The 

 sea-coasts, which are the seats of large cities and the centres of 

 population and trade, are also the most extensively affected with 

 tuberculosis — in the West Indian Islands, Panama, Nicaragua, 

 TSiexico, Yucatan, Columbia, Equador, Peru, Chili, Ceylon, 

 ■Guinea coast — ^while the sparsely peopled highlands of the same 

 countries are practically free. 



What is true of man is equally so of cattle. In the Gulf states 

 of this country, herds living in the open air are practically free 

 from tuberculosis, while in New. Orleans and other large cities, 

 the cows shut up in the confined stables and yards, are as tuber- 

 culous as those of the great cities of the north. So in many dis- 

 tricts in the northern states we find no bovine tuberculosis, while 

 in others, differing in no essential particular as regards geological 

 formation, altitude, exposure, and industrial use of the animal, 

 a large proportion are affected. 



Virulence. Tuberculosis has long been recognized as virulent. 

 •" It is indicated in the Mishna and other Jewish works as render- 

 ing the meat unfit for consumption, but to come to more modern 

 times, we find that throughout the seventeenth and eighteenth 

 centuries the flesh of tuberculous animals was excluded from 

 human food, alike by the civil and ecclesiastical laws of Europe. 

 •Tuberculosis in cattle was erroneously identified with syphilis of 

 man, which made a frightful. extension in the end of the fifteenth 

 century, spreading from the army of Charles VIII which had 

 "been engaged in the siege of Naples. This conviction lasted 

 until it was disproved about 1782. Though mistaken in the 

 identity of the two diseases, the fact that for centuries the com- 



