LETTER OF TRANSMITTAL. 



U. S. Department of AaRiouLTURE, 



Bureau of Animal Industry, 



Washington, B. C, August 2, 1889. 



Sir: I have the honor to submit herewith the report of the Board of 

 Inquiry appointed in December, 1888, to investigate certain contested 

 questions relating to the epizootic diseases of swine. This report suf- 

 ficiently indicates the nature of these questions, and consequently no 

 further explanation is needed in this letter. I would simply add a word 

 as to the available methods of prevention, since the report itself, al- 

 though perfectly correct in its statements, is liable to leave a misap- 

 prehension in the mind of the reader as to the work and policy of the 

 Bureau of Animal Industry. 



The earliest and most extensive series of experiments made after the 

 discovery of the germ of hog cholera, to determine the ef&cacy of inoc- 

 ulation as a preventive measure, were conducted at the Experiment 

 Station of this Bureau. These experiments, I believe, indicate with 

 greater certainty what may be expected from preventive inoculation 

 than do any other experiments which have been made up to this time. 

 Inoculation, however, was found unsatisfactory ; first, because of the 

 danger of spreading the contagion j and secondly, because the degree of 

 immunity produced was not deemed sufficient to counterbalance the 

 expense and disadvantages of the method. 



The fact that the chemical products developed during the multipli- 

 cation of the germs of hog cholera would create an immunity was 

 first demonstrated by the experiments of this Bureau ; and all that is 

 known of this subject was brought out by these investigations. I have 

 recognized the fact from the time I began the study of swine diseases 

 in the interest of this Department that this was one of the most prom- 

 ising lines of research j at the same time it is one of the most diflBcult 

 questions to investigate that is now before the scientific world, and the 

 reason our experiments have not been carried further is that we have 

 not had the laboratory facilities for this kind of work. 



While we recognize the fact that disinfection can not be depended 

 upon to prevent hog cholera without some change in the method of 

 handling hogs, particularly in the West, we feel quite certain from our 



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