438 BACILLI WHICH PRODUCE SEPTIOEMIA 



as large. It also produced a greater opacity in peptonized bouillon, and in 

 general showed a more vigorous growth in various nutrient media. It dif- 

 fered also in its pathogenic power, as tested upon rabbits, causing- death at a 

 later date or not at all ; and in fatal cases the swelling of the spleen and 

 necrotic foci in the liver, produced by the first-described species, were absent. 



Bang (1892) has obtained a bacillus from infected swine in Denmark 

 which corresponds with the American hog-cholera bacillus. In chronic 

 forms of the disease pneumonia and an extensive diphtheritic process in the 

 intestines occurred as a complication. This was found to be due to another 

 bacillus, called by Bang " vacuole-bacillus." This produced a fatal pleuro- 

 pneumonia when injected into the lungs in pigs. According to Bang, his 

 * 4 vacuole-bacillus " is without doubt identical with the swine-plague bacillus 

 of Salmon and Smith, and the disease of swine studied by him was a mixed 

 infection. The necrotic changes in the intestine, found in cases running a 

 chronic course, are believed by Bang to be due to still another bacillushis 

 "necrosis-bacillus." Affanas'sieff (1892) confirms the results previously ob- 

 tained by several independent observers as to the identity of the swine-plague 

 bacillus of Salmon and Smith with the Loffler-Schiitz bacillus. The only 

 difference observed was a difference in pathogenic virulence the bacillus 

 from America corresponding with a somewhat attenuated variety of that 

 from Germany. 



Welch (1894), as a result of his extended researches, arrives at the follow- 

 ing conclusion : 



"Our own conclusion as to the bacteria of Schweineseuche and of swine 

 plague is that no difference exists between them as regards morphology, 

 culture behavior, and pathogenic effects on rabbits, mice, and other labora- 

 tory animals. Cultures of each occur which are also indistinguishable by 

 inoculation of pigs. The only difference by laboratory experiment which 

 has thus far been brought out is that there occur Schweineseuche bacilli of 

 higher degree of virulence as tested on pigs than any swine-plague bac- 

 teria which have hitherto been isolated from pigs in this country. Another 

 point to be considered in this connection is that Schweineseuche occurs as 

 an independent disease in Germany without association with hog cholera, 

 whereas swine plague has not been shown to prevail with the same inde- 

 pendence as an epizootic in this country." 



Silberschmidt (1895) arrives at a different conclusion from that reached 

 by Smith, Welch, Bang, and others, He believes that the diseases of swine 

 known as hog cholera, swine plague, and infectious pneumo-enteritis are all 

 due to one and the same bacillus, which, however, varies considerably both 

 in its morphological characters and its pathogenic power. In view of the 

 results previously reached by equally competent bacteriologists, and especially 

 by Smith and by Welch in this country, we are not disposed to accept the 

 view maintained by Silberschmidt. 



Smith has described several varieties of the hog-cholera bacillus, and in 

 his account of the "hog-cholera group of bacteria " shows that the Bacillus 

 enteriditis of Gartner and the Bacillus typhi murium of Loffler belong to 

 this group. The characters of the different varieties (or species?) belonging 

 to the group are given by Smith in detail (United States Department of Agri- 

 culture, Bureau of Animal Industry, Bulletin No. 6, 1894), and the follow- 

 ing general statement is made: 



" If we attempt to sum up those characters which are to circumscribe the 

 hog-cholera group of bacteria we are at once confronted by the scarcity of 

 common character's. Pathogonesis, though of great importance from the 

 standpoint of pathology, is probably the last character acquired and 

 evident ly the most variable and most readily lost. If we base the unity 

 of this group on morphological and biological characters, we are like- 

 wise met by variations in size, absence of motility, variations in the ap- 

 pearancr <>f th- colonies. Then* are, however, certain underlying char- 



