G50 K]!:poiiT OF THE co:.i:.iissiONEii of agriculture. 



protect against the disease itself, the following experiment was per- 

 formed : 



Four pigs (Nos. 20:3, 20-i, 205, and 212) were inoculated April 2 with 

 l-^""^ of a seventh culture in beef infusion with 1 per cent, peptone one 

 day old. Four additional pigs (Nos. 20G, 207, 208, and 200) received 

 but 1'^° of the same culture. The remaining four of the same lot 

 (Nos. 203, 210, 211, and 213) were reserved as checks upon the experi- 

 ment. Of these, Nos. 203 and 213 had a temperature of 10G° F., and 

 hence were suspected of disease. This suspicion was soon confirmed 

 after they had been placed in a pen alone. Both had a severe diarrhea, 

 one dying April 11, the other April 13. The lesions were confined to 

 the mucous membrane of the large intestine, which was dotted with 

 numerous elevated lemon-yellow tough masses a few lines across, sim- 

 ulating ulcers. On close examination, however, this impression was 

 dispelled. These tough masses were easily removed in toto from the 

 mucosa, which presented a slight depression without any loss of sub- 

 stance. They were evidently exudates from the mucosa and perhaps 

 diphtheritic. There were no bacteria in the blood or in a bit of sjjleen 

 dropped into a culture tube. No development took place in either 

 tube. 



Of those inoculated with l^'', two died from the immediate effects 

 of inoculation. No. 204 died in eleven days and No. 212 in seven days. 

 In No. 204 a tough tumor had formed at the point of inoculation on 

 each side. The mucous membrane of the large intestine was com- 

 pletely necrosed and the spleen enlarged. In No. 212 local swelling 

 was present on one side. The stomach and large intestine were deeply 

 congested, with points of commencing ulceration in the latter. In 

 both animals the bacterium of hog-cholera was present in cover- 

 glass preparations of the spleen. Nos. 202 and 205 seemed to remain 

 unaffected by the inoculation. One month and a half later both w^ere 

 exposed to the disease in the large infected pen. A month later they 

 were removed with others to a clean pen, after having apparently re- 

 sisted infection. No. 202 was gradually wasting away and died July 

 24, more than two months after exposure. In the large intestine were 

 cicatrices of healed ulcers and such as were healing. The severest 

 lesions were in the lungs. Both were adherent by means of bands 

 to the costal pleura, and were extensively hepatized. No. 205 was 

 alive and well August 15. 



Of the second lot, which had received l^'^ of the same culture, 

 the results were nearly the same. Two succumbed to the inocu- 

 lation, one died of infection, and a fourth survived. No. 208 died 

 fifteen days after inoculation. Besides the inoculation swellings, en- 

 larged and congested spleen, the mucous membrane of the large in- 

 testine was covered with extensive deep ulcers and the walls much 

 thickened and softened. The corresponding lymphatics in the meso- 

 colon deep purple. No. 209 died in six days after inoculation. There 

 was general congestion and extravasation of blood in the internal 

 organs, involving the entire mucous membrane of the alimentary 

 tract, especially the large iniestine, the lymphatics and serous mem- 

 branes, the spleen and kidneys. Ulceration had not yet begun. In 

 both animals the spleen was crowded with bacteria and furnished 

 pure cultures of the specific germ. 



Nos. 206 and 207 were not affected by the inoculation. They were 

 exposed with the preceding lot, as indicated in the table. No. 207) 

 after apparently resisting the contagion in the infected pen for a 

 month, die<l July 18, after having been in a clean pen since June 21. 



