1 20 Journal of A gricultural Research voi. xiii, No. 2 



ance of first visible symptoms, and two susceptible pigs, No. 1093 and 

 1094, were placed in same pen. At the time of transfer pig 904 was 

 recorded as being off -feed, in poor condition, and as showing diarrhea. 



The two exposed pigs, No. 1093 and 1094, contracted cholera from con- 

 tact with the sick pig and showed the first visible symptoms on November 3. 

 Both of these pigs died on November 10. Pig 1094 showed hemorrhagic 

 lesions at autopsy and No. 1093 showed hemorrhagic lesions with ulcera- 

 tion of cecum. Pig 904, which furnished the exposure, died on October 

 30, showing hemorrhagic lesions with extensive ulceration of the cecum 

 and colon. 



In this experiment the disease was transmitted by contact as late as 

 the twenty-first day after the appearance of first visible symptoms. 



In the four experiments which have just been described, susceptible 

 pigs were exposed to sick pigs on the seventh, twelfth, fourteenth, and 

 twenty-first days after the appearance of first visible symptoms of sick- 

 ness. All of the exposed pigs contracted hog cholera as a result of the 

 exposure. 



The preceding experiments. No. V to IX, inclusive, show that hog 

 cholera is contagious at all stages, even including the stage of incubation. 

 They indicate also that an infected hog remains a source of danger at 

 least until the time of complete recovery. 



RECOVERED PIGS AS CARRIERS OF HOG CHOLERA 



Suspicion has long rested on the recovered pig as a possible carrier of 

 hog cholera, but there seems to be little, if any, experimental evidence on 

 this point. This lack of experimental evidence is no doubt largely due 

 to the difficulty of obtaining hogs which have had genuine attacks of 

 cholera and have subsequently made a complete recovery. 



In the course of the experiments which were carried out during the 

 summer and fall of 191 6, four pigs were secured which had suffered from 

 acute, typical hog cholera, and which had made apparently good recov- 

 eries. The following experiments were carried out with these animals. 



Experiment X. — Pig 893 was injected with virus on September 13, 

 1916, and within the usual time developed an acute case of cholera, but 

 made an apparently good recovery. The clinical record of this pig is 

 given in full in Table IX. 



