NATURE AND PREVENTION OF HOG CHOLERA. 



INVESTIGATIONS OF 1887. 



An extensive outbreak of hog cholera near the city of Washington 

 during the months of November and December, 1887, afforded the 

 opportunity of examining more carefully the condition of the lungs 

 in the various types of this disease as- contrasted with swine plague 

 or true infectious pneumonia. At the same time the bacteriological 

 examination re-affirmed the constant presence of the bacillus de- 

 scribed three years ago in genuine hog cholera and its causal relation 

 to this disease. It is to be hoped that the rather stubborn and wholly 

 unfounded position maintained in some quarters that there is no dis- 

 ease such as hog cholera independent of swine plague will be aban- 

 doned. This is the more important inasmuch as hog cholera is a 

 more prevalent and more virulent disease than swine plague. At least 

 five epizootics have been observed in the District of Columbia to one 

 of swine plague. In order to combat any bacterial disease it is ab- 

 solutely essential that all facts connected with the life history of the 

 bacteria be taken into account, and this implies the frank acceptance 

 of results of investigations if the evidence has been fully and unre- 

 servedly presented. 



The history of the outbreak, as far as could be ascertained, was 

 briefly as follows: On October 28, there were in all 119 swine, chiefly 

 young pigs, weighing from 50 to 100 pounds. Most of these had been 

 purchased in the city markets. At this same time 20 boar pigs were 

 castrated. Within two weeks these began to die, and soon after the 

 others took sick, dying at the rate of 3 to 4 a day. Less than three 

 weeks after the first deaths only 67 remained out of the 119. At 

 the end of the year only about a dozen were alive out of the entire 

 herd. These may have acquired an immunity. 



The animals were kept in pens on the top of a low hillock, sheltered 

 from the weather by large boxes. They were swill-fed, and this may 

 account for their feeble resistance to the disease. In most of them 

 the feeding had induced a cirrhosis of the liver, with softening of the 

 parenchyma. The origin 'of the disease could not be traced, as the 

 animals had come from various quarters. The city markets had 

 proved theniselves the source of disease in several purchases of pigs 

 for experimental purposes. 



The autopsy and bacteriological notes will be given in the order in 

 which the animals were examined, any general remarks being reserved 

 for the end. The rapidity with which the animals succumbed to the 

 disease made any very thorough examination quite impossible, since 

 it seemed more desirable to utilize all the material by examining those 

 organs most always diseased in hog cholera. Most attention was paid 

 to the lungs and the digestive tract, while the lungs and the spleen 



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