33G BOARD OF AGRICULTURE. [Jan. 



they have destroyed their dairy herds, have on post-mortem exam- 

 ination found them to be diseased, and have offered their informa- 

 tion and their example to the agricultural community in which they 

 reside, and to the market in their neighborhood. 



I understand that before this destruction took place a careful 

 investigation was made into the history and extent of the disease 

 in the herds, into the causes which produced the disease in those 

 localities, and into the length of time during which the disease had 

 existed. I suppose, moreover, neighboring herds were examined, 

 to ascertain how much disease still remained, and whether or not 

 the danger had been removed. It would be important and most 

 interesting to know the extent of tuberculosis in the great dairy 

 regions of the United States, and its comparative prevalence in 

 different climates and localities, and under the various methods 

 of housing and feeding. 



In diagnosing the contagious diseases of animals, we depend 

 largely upon the history of the case before us and the exposure of 

 the animal, so difficult is it to arrive at a conclusion except by 

 history or by an autopsy. In examining non-contagious diseases, 

 we have no historical facts to guide us, and must of necessity 

 grope in the dark, with a dumb and unintelligent case before us, 

 in which we depend on symptoms alone, with no knowledge what- 

 ever of the sensations. It would be no easy task for the most 

 skillful veterinary surgeon to decide how much tuberculosis, if any, 

 exists in a herd of apparently healthy animals, or in a badly con- 

 ditioned herd which has been wintered on hard fare, even when ho 

 has discovered the disease by autopsy in the region where the 

 herd is kept. And, when an examination reveals the existence of 

 the disease in localities supposed to be healthy, the question might 

 arise, How many generations of men have been exposed to its 

 influence, unconscious of any ill effects? 



In an economical point of view, the possibility of investigating, 

 ascertaining to a certainty, and eradicating, tuberculosis, in a wido 

 agricultural community, counting the cost and the suspension of 

 business, presents a startling problem, as does also the inquiry as 

 to the sources from which a supply of healthy cattle can be surely 

 obtained, to take the places of those that have been destroyed. 

 The questions connected with the human economy also are most 

 important, and should not be overlooked or settled by mere asser- 

 tion. The predisposing causes of consumption, which is the most 

 common form in which tuberculosis presents itself in the human 

 subject, should not be forgotten. The careful observer knows 

 well how much food, clothing, habits of life, inheritance, location 

 of dwelling, have to do with the development of a scrofulous dia- 



