IN SUSCEPTIBLE ANIMALS. 507 
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 oceur 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 Girtner 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: ; ; 
“Tf 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 characters. Pathogenesis, though of great importance from the 
standpoint of pathology, is probably the last character acquired and 
evidently 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- 
pearance of the colonies. There are, however, certain underlying char- 
acters, as expressed by the behavior of these bacteria in bouillon con- 
taining dextrose, saccharose, and lactose, which I think will serve as a very 
important group character, differentiating such groups sharply from the 
colon group. I would therefore suggest that for the present all bacteria 
whose size approximates that of this group, which do not liquefy gelatin, and 
whose fermentative properties are the same as those described for this group, 
should be ranged under it. Future investigations into the biochemical char- 
acters of these varieties or sub-species may reveal other differential charac- 
ters, but the time has not yet come when such laborious work will be under- 
taken oma sufficiently extensive scale to be of any service in differentiating 
varieties and sub-species.” : 
Selander in 1890, and Metschnikoff in 1892, have reported a rapid increase 
in virulence of the bacillus of hog cholera by successive inoculations in 
rabbits or pigeons. Moore (1894) has shown that this is a mistake, and that 
the bacteriologists named probably did not experiment with cultures of the 
hog-cholera bacillus, as they supposed, but that their experiments were 
made with the bacillus of swine plague—Bacillus septiceemize hemorrhagi- 
cze—which when passed through a series of rabbits attains a notable increase 
in pathogenic virulence. eich : 
In a recent article, Klein, of London (1895) says: ‘‘ The bacillus of 
English swine plague, which I described in 1884, in Virchow’s Archiv, as 
é 
