350 



INFECTIVE DISEASES. 



times as long as Bacterium termo ; and in preparations made from 

 diseased organs they were found to possess a very narrow trans- 

 parent halo, a sort of hyaline gelatinous capsule. Inoculation of 

 cultures failed to produce the lesions found in animals naturally 

 infected. Two pigs were inoculated, one with a sub-culture from the 

 swollen bronchial gland of a pig that had died of pig-typhoid, and 

 a second with a culture obtained from the spleen of a mouse that 

 had been inoculated from another case of swine fever. After two 

 days the inguinal glands near the seat of inoculation became swollen, 

 and the temperature rose slightly. After three or four weeks the 

 animals recovered. 



Mice on the fifth or sixth day after inoculation showed symptoms 



of illness, then respiration became 

 superficial and slow. Death 

 occurred on the sixth or seventh 

 day. 



Rabbits showed a rise of 

 temperature, and death followed 

 between the fifth and eighth days, 

 the temperature falling before 

 death. At the post-mortem ex- 

 amination there was usually 

 peritonitis, with copious exuda- 

 tion. The kidney, spleen, and 

 liver were enlarged and dark in 

 many cases, there was red hepa- 

 tisation of the lobes of the lungs, 

 and generally pericarditis and haemorrhage under the pericardium. 



In 1885 Salmon, in the annual report of the United States 

 Bureau of Animal Industry, published the result of his investigations 

 into American hog cholera, which is identical with English pig typhoid. 

 A motile figure-of-eight bacterium was isolated, each part being 

 about twice as long as broad. The bacterium grew on nutrient 

 gelatine without liquefying it, and on potato produced a brownish 

 growth ; broth tubes became turbid on the following day. Colonies 

 in plate- cultivations were oval or circular, and brownish in colour. 

 Six pigs inoculated subcutaneously were all said to have died of hog 

 cholera, and the bacterium was again obtained from the blood of 

 the heart and spleen. The bacteria proved fatal to mice, rabbits, 

 guinea-pigs, and pigeons. 



In 1893 Welch and Clement described the hog-cholera bacillus 

 as variable in form, and they further stated that a culture obtained 



FIG. 141. BLOOD OP FRESH SPLEEN OF 



A MOUSE, AFTER INOCULATION WITH 



(KLEIN.) 



BACILLUS No. 2. 



