INFECTIOUS SWINE DISEASES IN THE UNITED STATES. 
823 
culture of which was kindly sent to Dr. Salmon by Metsch- 
nikoff, it was found to be the bacillus of swine plague. The 
results which they had reported were not strikingly different 
from those which we have obtained under certain conditions, 
with the swine-plague organism. To understand their results' 
in the light of those obtained in this country, it is necessary to 
read swine plague where they have written hog cholera. By 
doing this, the confusion which otherwise will be caused by 
their articles on the hog-cholera bacillus will be avoided. 
In the last edition of his Text Book of Bacteriology and In¬ 
fective Diseases, 1897, Crookshank writes that, “the bacillus 
isolated by Loefffer and Schiitz from swine fever in Germany 
{Schzveineseuche) has been identified with the bacillus isolated 
by Salmon and Smith from hog cholera in America, and with 
the bacillus of rabbit septicaemia and of fowl cholera.” Such 
statements are certainly confusing. 
Again we find the influence of Billings’ interpretations, pub¬ 
lished long after the bacteria in question were described, in 
which he states that the bacillus of swine plague* is actively 
motile. During the past year I have received statements from 
two distinguished bacteriologists of the existence of motile swine- 
plague bacilli. This is important, for it shows an unmistakable 
error somewhere. If we have been in the wrong concerning the 
motility of this organism, we are ready upon sufficient evidence 
to retract, but thus far we have not observed either independent 
movement or the organs of locomotion (flagella) on this species 
of bacteria. It is not surprising, however, that after the appear¬ 
ance of so much literature in which the swine-plague bacillus 
has been assigned the morphology and properties of the bacillus 
of hog cholera that confusion should arise. 
In comparing these two species of bacteria it is necessary for 
our purpose to call attention simply to their more essential 
properties which may be considered of differential value. In 
order that these may be more easily contrasted I have arrang'ed 
them in like order in parallel columns. 
* He is writing of the disease known to the Bureau of Animal Industry as hog cholera. 
