1890.] PUBLIC DOCUMENT — No. 4. 327 



3. Milk was used nine times from cows in wliich the disease 

 was localized in the lung. 



From these twenty cases the milk was proven to be infectious in 

 eleven. The percentage of positive results, when arranged in 

 accordance with the three groups above given, was eighty per cent 

 in the first group (milk from cows in a very advanced stage of the 

 disease), sixty-six per cent in the second group, and thirty-three 

 per cent in the third. 



Experiments more interesting still, and more conclusive, 

 have been made by Dr. Ernst, and directly under his own 

 eye, in the bacteriological laboratory of the Harvard Medical 

 School ; while the feeding experiments have been made, and 

 the experimental animals have been kept, upon a farm in the 

 country, expressly prepared for this special purpose, and 

 have extended over quite a long period of time and been 

 attended with the utmost care. Full notes of these experi- 

 ments will be found in the "Transactions of the Association 

 of American Physicians," vol. lY., 1889. Dr. Ernst says the 

 results enumerated "are, to a certain extent, preliminary; 

 that is to say, they are but part of tlie work upon this 

 subject which is being done under the auspices of the 

 Massachusetts Society for the Promotion of Agriculture. 

 The work will not be completed, at any rate, until next 

 year. They show, however, first, and emphatically, that the 

 milk from cows affected with tuberculosis in any part of 

 the body may contain the virus of the disease ; second, that 

 the virus is present, whether there is disease of the udder or 

 not ; third, that there is no ground for the assertion that 

 there must be a lesion of the udder before the miik can 

 contain the infection of tuberculosis ; fourth, that, on the 

 contrary, the bacilli of tuberculosis are present and active in 

 a very large proportion of cases in the milk of cows affected 

 with tuberculosis, but with no discoverable lesion of the 

 udder." 



Is tuberculosis contagious, or is it not? It must be either 

 one or the other. Such diseases as small-pox, measles, scarlet- 

 fever and diphtheria are universally accepted as such ; and the 

 same reasoning which has led the general public as well as the 

 profession to that conclusion, if the fiicts are the same, ought 

 to bring them to the same conclusion in regard to tuberculosis. 



