BUREAU OF ANIMAL INDUSTRY. (,'43 



stipcrficial ulcerations. In No. 283 tho congestion of spleen, and ulcenition with 

 coiiK 'i^tiou of tlio large intestine, were also very marked. No. 266 presented the 

 BiOnic lesions. The ulcers in the caecum were from i to i inch across. No. 2130 

 (check) differed from the preceding cases in presenting severer lesions; gi-eatly en- 

 larged and congested spleen and lymphatic glands, entire superficial necrosis of tlie 

 caH'uin and upper portion of colon, witli intense congestion of the mucosa of the 

 entire colon and great thickening of tlie waUs; extensive extravasation of blood be- 

 neath the mucosa of duodenum. 



C)f the second lot of four ti-eated in the same way, No. 267 presented very severe les- 

 ior.j, consisting of intense congestion and extravasation, involving the spleen, lym- 

 phatic glands, lungs, and kidney. The left lung was almost entirely adherent to costal 

 pleura. There was considerable hemorrhage in the pelvis of botli kidneys. The 

 lai'ge intestine was least changed, the mucosa being slightly ulcerated and containing 

 somi; hcniorrliagic spots and jioints. This animal was first to die out of this lot of 

 eight. In No. 2'68 the congestion involved the lymphatic glands generally, and the 

 mucosa of the lai'ge intestine, which was extensively necrosed in its upper portion. 

 No. 269 resembled No, 267 in the severity of the lesions. The lungs were not af- 

 fected, however, wliile the ulceration of csscum and upjier colon was very extensive 

 and deep. No. 270 (check) presented extensive ulceration of the large intestine and 

 a greatly enlarged spleen. In five cases the spleen contained the bacteria of hog- 

 cliolera more or less aliunduntly. In tv^^o none could be seen on one or two cover- 

 glasses. No local swelUng had developed at the poinfe of injection in any of the 

 inoculated animals. 



In tliis experiment no immunity was produced, since the animals 

 succumbed to the infection very quickly and showed themselves very 

 susceptible, as indicated by the severe lesions of the internal organs 

 in general. 



The foregoing exjjeriments, aimed at producing immunity by the 

 injection of the chemical products or ptomaines, were, as a whole, un- 

 successful with reference to pigs, although successful upon pigeons. 

 If larger doses of culture liquid had been given and in separate doses 

 extending over longer periods of time the results might have been 

 positive even upon pigs. The cost of the culture fluid being too great 

 to make the experiment of practical value on a large scale, no further 

 attempts were made in this direction for the present. 



As the etiology of this very virulent disease had been sufficiently 

 demonstrated by the experiments reported last year, no particular 

 attention was paid to a determination of the presence of the bacteria 

 of hog-cholera by cultures. Usually the spleen was examined by 

 means of cover-glass preparations whenever time allowed, and in most 

 cases large numbers of the specific bacterium were present. In the 

 many cultures from spleens made from these and subsequent cases to 

 carry out the inoculations none other than the motile bacterium of 

 hog-cholera appeared in these cultures. At the same time many 

 minor experiments upon mice were made for various purposes, and 

 in all the characteristic lesions described in the second report were 

 found associated with the specific bacterium. 



Inoculations with unattenuated cultures. 



While the tests for conferring immunity upon pigs by the injection 

 of heated virus were being carried on it was thought advisaljle to ex- 

 periment in the same direction with the unattenuated cultures them- 

 selves. A lot of animals was at first inoculated twice with very 

 small quantities, the period between the two inoculations being about 

 two weeks. This time was sufficient to reveal any disease which might 

 have been induced by the inoculations. Two weeks after the second 

 inoculation the animal was infected either by feeding the interna] 

 organs of pigs which had died of the disease or by exposing it to 



