LIST OF ILLUSTRATIONS. Page. INVESTIGATION OF HOG-CHOLERA AND SWINE-PLAGUE : Plate I.-Ulcerated cæcum of a pig inoculated with the blood from a case of hog-cholera.... 104 Plate II.-Ulcerated cæcum of a pig fed with viscera from a case of 104 Plate VIII.-Hog-cholera and swine-plague bacteria..... 104 Plate IX.-Swine-plague bacteria.... 104 Plate X.-Contagious pleuro-pneumonia. Lung of a diseased steer 104 Plate XI.-Contagious pleuro-pneumonia. Lung of a cow slaught ered in Baltimore, Md..... 104 Plate XII.-Contagious pleuro-pneumonia. Lung of a cow slaught LETTER OF TRANSMITTAL. SIR: I have the honor to submit herewith the Third Annual Report of the Bureau of Animal Industry, containing an account of the work during the past year for the suppression of the disease known as contagious pleuro-pneumonia or lung plague of cattle, and also of the investigations of this and other diseases of our domestic animals, and in regard to the present condition of the animal industry of the United States. Since writing my Annual Report for 1885, the outbreak of pleuropneumonia which began in Harrison County, Kentucky, in 1884, and which was allowed to continue there until March of this year, has been entirely suppressed. This would not have been possible except for the act of the legislature authorizing the condemnation of the affected animals and providing compensation for them, and the cordial co-operation of the State Board of Health with the representative of this Bureau. All of the exposed animals were slaughtered and deeply buried, the stables and yards disinfected, and the locality kept under supervision until all danger of a re-appearance of the disease was past. Dr. W. H. Wray deserves much credit for the professional skill and business capacity shown by him in the management of this outbreak, which for many reasons was unusually difficult to control. The most important event of the year was the discovery of pleuropneumonia among the cattle kept in the distillery stables of Chicago, and later among the cows pasturing on the commons of that city and some of the surrounding towns. The disease had existed there for a considerable time, and for this reason its origin could not be definitely ascertained. There can be little doubt, however, that it is a continuation of the outbreak of 1884, at which time herds were affected at Elmhurst, Saint Charles, and Geneva, either place being sufficiently near to account for the extension to Chicago. As a considerable number of cattle were exposed at Geneva, where a strict quarantine could not be maintained at the time, it seems most probable that the contagion was carried by cattle going from there to Chicago. The existence of such a dangerous plague in this great commercial center, and so near to the Union Stock Yards, through which cattle are passing to all parts of the country, is a menace to 5 the cattle industry of the most serious character. Fortunately the managers of the Union Stock Yards have adopted stringent regulations which prevent the admission of any animals from Cook County, and, consequently, the traffic through these yards has been protected since the presence of the plague was discovered. While the existence of the disease in the distillery stables has attracted much attention because of the number of animals affected and exposed, it does not deserve the attention there that it does among the cows of the owners of small herds about the city. In the distilleries the cattle can be easily quarantined and guarded, and as all are intended for slaughter within a comparatively short time. there is neither the difficulty nor the expense which would be encountered in disposing of the same number of animals in any other situation. The exposed animals outside of the distilleries are, therefore, of much greater interest to the country, and immediate measures are needed to crush out the contagion which is being propagated among them. This Department has not sufficient authority or funds to accomplish this, but it was hoped that with the co-operation of the State Live Stock Commission this end might be speedily reached. Unfortunately the State Commission appear disinclined to take rigorous action in reference to the city cows, and also differ with us as to the measures which it is necessary to enforce. Maryland was the first State to accept the rules and regulations of this Department for co-operation, and owing to the well-known prevalence of the disease there, work was begun almost immediately. The inspectors have examined 1,221 different lots of cattle during the year, containing 11,722 individual animals. Of these 219 lots were found infected, and 652 animals were reported as affected with pleuro-pneumonia. The appropriation for slaughtering sick animals did not become available until July 1, 1886. For the six months ending December 31, 1886, the Department purchased and slaughtered in this State 336 animals affected with contagious pleuro-pneumonia. From the information at hand we judge that the prevalence of this disease has not been materially modified in the other infected States since previous reports were made. The investigations of swine diseases during the current year have yielded very important results. It has been shown that there are really two diseases of swine, both of which are widely distributed and both communicable, which have not heretofore been distinguished from each other. Although these two diseases may co-exist at the same time and in the same herd, they are often found separate, and have very different characters. This discovery was foreshadowed in the two previous reports of the Bureau, in one of which the bacterium causing swine-plague was described as a micrococcus and in the other as a bacterium. Our subsequent investigations have demonstrated that each of these germs produces a distinct disease, and in order to distinguish between them we call the micrococcus disease swine-plague, and the bacterium disease hog-cholera. The investigations of the year abundantly confirm the important discovery, announced in the report for 1885, that the pathogenic germs produce, during their multiplication in culture tubes, a chemical substance which may be used to produce immunity from that particular contagion. This discovery opens a most promising field for investigation, and it indicates that in the future we shall be able to prevent the contagious diseases of both animals and people by the administration of harmless chemical compounds. It will require a long series of investigations, however, to learn how to separate these chemical compounds from the other substances in the culture liquids, to determine their chemical composition and the best methods of producing them artificially. The experiments which have been made to bring out the characters of the germs of these diseases and the most active disinfectants for their destruction, are of great interest and value from a practical point of view, and when completed will give accurate information of the means that can be employed in combating them. For the careful and accurate manner in which the experiments referred to above have been carried out, I am indebted to Dr. Theobald Smith, director of the laboratory, and to Dr. F. L. Kilborne, director of the experiment station, both of whom have shown the most commendable activity and interest in the work, and whose intelligence and zeal have enabled us to satisfactorily decide some of the most difficult questions which modern science has been called upon to elucidate. In addition to the report of the Chief of the Bureau, this volume contains a very important report by Col. H. M. Taylor, agent of the Bureau of Animal Industry, on "The condition of the range cattle industry;" a valuable report by Edward W. Perry "On the cattle trade and allied industries of Michigan, Wisconsin, and Tennessee;" and a most interesting report by Mr. A. S. Mercer on "The cattle industry of California." Those papers, in connection with George W. Rust's excellent monograph on "Calf raising on the plains;" and the letter of the Commissioner of Agriculture on the "Dressed meat traffic," make a notable contribution to our knowledge of the great cattle industry of the United States. The "Investigation of the 'Loco' plant and its effect on animals," by Dr. M. Stalker, and also the investigation of "Staggers" among horses, by Dr. William H. Harbaugh, will be of much interest in the localities where these troubles abound. To the above has been appended copies of the laws bearing upon animal diseases which have been passed by the legislatures of the several States since the publication of the last report. A knowledge of these laws has become indispensable to those engaged in shipping stock from one State to another. The details of the cattle inspections conclude the volume and are given in full. Respectfully submitted. D. E. SALMON, Chief of the Bureau of Animal Industry. Hon. NORMAN J. COLMAN, Commissioner of Agriculture. |