1 1 8 Journal of Agricultural Research voi. xiii. No. 3 



Four pigs, No. 1097X, 1098X, 1099, and 1 100, were injected, each with 5 

 c. c. of virus blood on November i and were placed in the same pen. All 

 of these pigs showed first visible symptoms on the fifth day after inocu- 

 lation and developed the usual cholera symptoms. It was the inten- 

 tion to remove two of these sick pigs to a clean, disinfected pen at the 

 end of 14 days, when the pigs would be in the late stages of the disease, 

 and to expose two susceptible pigs with them; and two susceptible 

 pigs were to have been exposed with the two pigs remaining in the 

 original, infected pen. Pig iioo, however, died on the tenth day, ex- 

 hibiting extensive hemorrhagic lesions at autopsy, so the experiment 

 had to be modified as follows: 



On November 11, ten days after inoculation and seven days after 

 the appearance of first visible symptoms, pig 1099 was transferred to a 

 pen which had been cleaned and disinfected and the disinfectant subse- 

 quently removed by washing. On the same date two susceptible pigs. 

 No. 1 1 38, and 1139, were placed in the disinfected pen with the sick 

 pig. No. 1099. At the time of transfer, pig 1099 showed a temperature 

 of 105.6° F. and was recorded as off feed and showing weakness, con- 

 junctivitis, and diarrhea; this pig died four days later, on November 15, 

 and the autopsy revealed estensive hemorrhagic lesions and ulceration 

 of the cecum and colon. The two susceptible pigs, No. 1138 and 1139, 

 promptly contracted hog cholera from contact with the sick pig, showing 

 first visible symptoms on November 16, five days after exposure, and 

 were found dead on November 2 1 ; both showed extensive hemorrhagic 

 lesions at autopsy. 



On November 11, two susceptible pigs, No. 1142 and 1143, were 

 placed with the two remaining sick pigs, No. 1097X and 1098X, which 

 had been left in the original, infected pen. At this time pig 1097X 

 showed a temperature of 106.2° F. and was recorded as off feed and as 

 showing conjunctivitis, weakness, and diarrhea; pig 1098X showed a 

 temperature of 106.4° and was recorded as off feed and showing con- 

 junctivitis and weakness. Pigs 1097X and 1098X both died on Novem- 

 ber 14, and both showed extensive hemorrhagic lesions at autopsy. 

 The two susceptible pigs. No. 1142 and 1143, promptly contracted hog 

 cholera, showing first visible symptoms on November 16, five days after 

 exposure; they were found dead on November 21, and both showed 

 extensive hemorrhagic lesions at autopsy. 



It will be noticed that there was no difference in the results in the 

 exposure in the clean, disinfected pen and the exposure in the original, 

 contaminated pen? in other words, the contact of the susceptible pigs 

 with the sick pigs was the essential factor in the conveyance of the 

 disease, and the additional pen infection in the one case had no apparent 

 effect on the development of the disease in the exposed pigs. 



