236 
D. E. SALMON. 
had been suppposed, but were entirely different and distinct, based 
one line of their argument upon the different effects which fol¬ 
lowed the inoculation of certain species of animals with virus 
from the two sources. Rabbits were found very susceptible to 
charbon fever, but very refractory to symptomatic charbon, and 
bovine animals were equally susceptible to the former disease at 
all ages, while their susceptibility to the latter was confined to 
the period between six months and three or four years of age. 
Now, if we study the virus of rouget and hog cholera from 
the same point of view we will find even stronger evidence that 
they are distinct from each other. Rouget virus is extremely 
fatal to pigeons, and one of these birds inoculated with only a 
fraction of a drop of blood from an affected animal is almost cer¬ 
tain to contract the malady and die from it. The experiments of 
Pasteur, Schutz, Lydtin, and many others demonstrate this fact. 
On the other hand Klein has made many experiments from which 
he maintains that pigeons are entirely insusceptible to the virus of 
pneumo-enteritis of hogs in England. The writer’s experiments 
in this country show that while pigeons are quite refractory to 
hog cholera virus they will contract the malady if inoculated with 
a large dose of a virulent culture. 
Again, the experiments of Schutz, Loeffler, Coruevin and 
others show very conclusively that guinea pigs are entirely insus¬ 
ceptible to the virus of rouget, and they cannot be made to con¬ 
tract it even when inoculated with enormous doses. On the 
other hand Klein found these animals partially susceptible to the 
contagion of pneumo-enteritis. In the experiments of the Bureau 
of Animal Industry guinea pigs have been found extremely sus¬ 
ceptible to the virus of hog cholera, and some of these animals 
have sickened from doses of less than one-two-hundred-and-fiftieth 
of a drop. 
Unless I am greatly mistaken, these experiments are, of them¬ 
selves, sufficient to show a profound and radical difference in the 
nature of the virus from these diseases which Dr. Liautard con¬ 
siders identical. I do not believe that in the whole domain of 
pathology an instance can be cited where the virus of any one 
