EEPOET OF THE BUEEAU OF ANIMAL INDUSTEY. 141 



able to assume that the microbe in these cases multiplied in the 

 abscesses only. When, however, the same disease in rabbits was 

 caused by inoculating them subcutaneously with the contents of the 

 caecum of healthy swine, this theory was abandoned, for it showed 

 that whatever caused the disease must have been normally present 

 in the intestines, very probably as a putrefactive organism. 



From a few cases, however (lung Nos. 1, 8, 9; intestine No. 8), swine 

 plague bacteria were obtained, and without doubt the disease was 

 due to these germs. The lung lesions of Nos. 8, 9, and 10 were well- 

 nigh sufficient to make a diagnosis of swine plague, but the existence 

 of intestinal lesions (ulcers in No. 2, 7) without any appreciable dis- 

 ease of the lungs had not yet been encountered in Eastern outbreaks 

 of swine plague, where extensive pneumonic and less frequently pleu- 

 ritic lesions have thus far proved the only reliable diagnostic sign. 

 The swine plague theory will likewise interpret the negative results 

 of many inoculations. Swine plague bacteria are easily destroyed by 

 drying, in ordinary water, and in putrefactive media. Some of the 

 animals (swine Nos. 4, 5, and 6) had been dead from thirty-six to 

 forty-eight hours, and meanwhile exposed to a temperature below 32 

 F. Under such circumstances any swine plague bacteria present in 

 the digestive tract may have perished even before the autopsies were 

 made. 



Taking these examinations, together with previous work on swine 

 plague in the East, into consideration, we must, for the present at least, 

 regard the disease not hog cholera but swine plague, basing this infer- 

 ence on the absence of hog cholera and the presence of swine plague 

 germs. The negative results from the cases examined on Farm B are 

 explained by the perishable nature of the swine plague germ, espec- 

 ially in the putrefying contents of the intestinal tract. * The following 

 very interesting case certainly favors the theory that swine plague 

 alone was decimating the hogs in that locality: 



A gentleman near Mason City, Iowa, had lost during the fall about 

 45 swine, valued at $800. The last ones succumbed about six weeks 

 ago. Several opened by him had the lungs badly diseased. The in- 

 testines were not examined. One of the animals had survived the 

 disease and was now (November 14) to all appearances recovered and 

 in very good condition. The owner, however, was willing to sacrifice 

 the animal, as he believed the lungs diseased. On post mortem ex- 

 amination the abdominal organs were found healthy but the lungs 

 extensively diseased. The left lung was firmly adherent by short 

 bands of connective tissue fibers to the ribs and diaphragm, so that 

 it was well-nigh J.mpossible to remove it without considerable lacera- 

 tion. It was shrunken to a small mass, and in its substance were six 

 or seven cavities as large as marbles filled with a soft, pultaceous mat- 

 ter. The walls of these cavities were at least one-eighth inch thick, 

 made up of dense fibrous tissue and stained uniformly on the inside 

 a dark bluish red. The right lung was adherent in several places to 

 the ribs, but contained no abscesses. 



* In view of the result of investigations made in the laboratory of the Bureau 

 during the first half of 1889, on an outbreak of swine disease in Maryland, it is not 

 improbable that the swine disease under consideration is likewise a mixture of two 

 diseases, swine plague and a peculiar, modified form of hog cholera, to which the 

 intestinal lesions in most of the cases may be due. The bacillus of this modified 

 form differs in many respects from the bacillus of true hog cholera, and demands 

 for its detection a procedure quite different from that which is sufficient for the true 

 *io cholera bacillus. 



